LIBRARY 

OF    THE 

UNIVERSITY  OF  CALIFORNIA. 
Class 


Gas-Engines  and 
Producer-Gas  Plants 


A  PRACTICE  TREATISE  SETTING  FORTH  THE  PRINCI- 
PLES OF  GAS-ENGINES  AND  PRODUCER  DESIGN,  THE 
SELECTION  AND  INSTALLATION  OF  AN  ENGINE,  CON- 
DITIONS OF  PERFECT  OPERATION,  PRODUCER-GAS 
ENGINES  AND  THEIR  POSSIBILITIES,  THF  CARE  OF  GAS- 
ENGINES  AND  PRODUCER-GAS  PLANTS,  WITH  A  CHAP- 
TER ON  VOLATILE  HYDROCARBON  AND  OIL  ENGINES 


BY 

R.   E.   MATHOT,   M.E. 

Member  of  the  Socie'te'  des  Ingenieurs  Civils  de  France,  Institution  of 

Mechanical  Engineers,  Association  des  Ingenieurs  de 

1'Ecole  des  Mines  du  Hainaut  of  Brussels 


TRANSLATED   FROM  ORIGINAL  FRENCH  MANUSCRIPT  BY 

WALDEMAR   B.   KAEMPFFERT 

WITH  A  PREFACE  BY 

DUGALD   CLERK,  M.  INST.  C.E.,  F.C.S. 
ILLUSTRATED 


NEW   YORK 

THE  NORMAN  W.  HENLEY  PUBLISHING  COMPANY 

132   NASSAU    STREET 
1905 


Copyright,    1905,   by 
THE  NORMAN  W.    HENLEY   PUBLISHING  COMPANY 

Also,  Entered  at  Stationers'   Hall  Court,  London,   England 
All  Rights  Reserved 


COMPOSITION,  ELECTROTYPING  AND  PRESS- 
WORK  BY  TROW  DIRECTORY,  PRINTING  AND 
BOOKBINDING  COMPANY,  NEW  YORK,  U.  S.  A. 


PREFACE 
TO 

"MATHOT'S    GAS-ENGINES   AND 
PRODUCER-GAS"  PLANTS  " 

BY 

DUGALD  CLERK,  M.lNST.C.E.,  F.C.S. 

MR.  MATHOT,  the  author  of  this  interesting  work, 
is  a  well-known  Belgian  engineer,  who  has  devoted 
himself  to  testing  and  reporting  upon  gas  and  oil 
engines,  gas  producers  and  gas  plants  generally  for 
many  years  past.  I  have  had  the  pleasure  of  knowing 
Mr.  Mathot  for  many  years,  and  have  inspected  gas- 
engines  with  him.  I  have  been  much  struck  with  the 
ability  and  care  which  he  has  devoted  to  this  subject. 
I  know  of  no  engineer  more  competent  to  deal  with 
the  many  minute  points  which  occur  in  the  installation 
and  running  of  gas  and  oil  engines.  I  have  read  this 
book  with  much  interest  and  pleasure,  and  I  consider 
that  it  deals  effectively  and  fully  with  all  the  principal 
detail  points  in  the  installation,  operation,  and  testing 
of  these  engines.  I  know  of  no  work  which  has  gone 
so  fully  into  the  details  of  gas-engine  installation  and 
up-keep.  The  work  clearly  points  out  all  the  matters 
which  have  to  be  attended  to  in  getting  the  best  work 

V 

14 1860 


vi  Preface 

from  any  gas-engine  under  the  varying  circumstances 
of  different  installations  and  conditions.  In  my  view, 
the  book  is  a  most  useful  one,  which  deserves,  and  no 
doubt  will  obtain,  a  wide  public  recognition. 

DUGALD  CLERK. 

March,  1905. 


INTRODUCTION 

THE  constantly  increasing  use  of  gas-engines  in  the 
last  decade  has  led  to  the  invention  of  a  great  number 
of  types,  the  operation  and  care  of  which  necessitate 
a  special  practical  knowledge  that  is  not  exacted  by 
other  motors,  such  as  steam-engines. 

Explosion-engines,  driven  by  illuminating-gas,  pro- 
ducer-gas, oil,  benzin,  alcohol  and  the  like,  exact 
much  more  care  in  their  operation  and  adjustment 
than  steam-engines.  Indeed,  steam-engines  are  regu- 
larly subjected  to  comparatively  low  pressures.  The 
temperature  in  the  cylinders,  moreover,  is  moderate. 

On  the  other  hand,  the  explosion-motor  is  irregu- 
larly subjected  to  high  and  low  pressures.  The  tem- 
perature of  the  gases  at  the  moment  of  explosion  is 
exceedingly  high.  It  is  consequently  necessary  to  re- 
sort to  artificial  means  for  cooling  the  cylinder;  and 
the  manner  in  which  this  cooling  is  effected  has  a  very 
great  influence  on  the  operation  of  the  motor.  If  the 
cooling  be  effected  too  rapidly,  the  quantity  of  gas 
consumed  is  considerably  increased;  if  the  cooling  be 
effected  too  slowly,  the  motor  parts  will  quickly  de- 
teriorate. 

In  order  to  reduce  the  gas  consumption  to  a  mini- 
mum, a  matter  which  is  particularly  important  when 


vu 


viii  INTRODUCTION 

the  motor  is  driven  by  street-gas,  the  explosive  mixture 
is  compressed  before  ignition.  Only  if  all  the  parts 
are  built  with  joints  absolutely  gas-tight  is  it  possible 
to  obtain  this  compression.  The  slightest,  leakage  past 
the  valves  or  around  the  piston  will  sensibly  increase 
the  consumption. 

The  mixture  should  be  exploded  at  the  exact  mo- 
ment the  piston  starts  on  its  working  stroke.  If  igni- 
tion occur  too  soon  or  too  late,  the  result  will  be  a 
marked  diminution  in  the  useful  effect  produced  by 
the  expansion  of  the  gas.  All  ignition  devices  are 
composed  of  delicate  parts,  which  cannot  be  too  well 
cared  for. 

It  follows  from  what  has  thus  far  been  said  that  the 
causes  of  perturbation  are  more  numerous  in  a  gas  than 
in  a  steam  engine;  that  with  a  gas-engine,  improper 
care  will  lead  to  a  much  greater  increase  in  consump- 
tion than  with  a  steam-engine,  and  will  cause  a  waste 
in  power  which  would  hardly  be  appreciable  in  steam- 
engines,  whether  their  joints  be  tight  or  not. 

It  is  the  purpose  of  this  manual  to  indicate  the  more 
elementary  precautions  to  be  taken  in  the  care  of  an 
engine  operating  under  normal  conditions,  and  to  ex- 
plain how., repairs  should  be  made  to  remedy  the  in- 
juries caused  by  accidents.  Engines  which  are  of  less 
than  200  horse-power  and  which  are  widely  used  in  a 
small  way  will  be  primarily  considered.  In  another 
work  the  author  will  discuss  more  powerful  engines. 

Before  considering  the  choice,  installation,  and  oper- 
ation of  a  gas-engine,  it  will  be  of  interest  to  ascertain 


INTRODUCTION  ix 

the  relative  cost  of  different  kinds  of  motive  power. 
Disregarding  special  reasons  which  may  favor  the  one 
or  the  other  method  of  generating  power,  the  net  cost 
per  horse-power  hour  will  be  considered  in  each  case 
in  order  to  show  which  is  the  least  expensive  method 
of  generating  power  in  ordinary  circumstances. 

R.    E.    MATHOT. 

MARCH,    1905. 


TABLE    OF    CONTENTS 


CHAPTER  I 

PAGE 

MOTIVE    POWER    AND    COST   OF   INSTALLATION     .     .        i 


CHAPTER  II 

SELECTION    OF   AN    ENGINE 

The  Otto  Cycle.— The  First  Period.— The  Second  Period.— The 
Third  Period. — The  Fourth  Period. — Valve  Mechanism. — Ignition. 
— Incandescent  Tubes. — Electric  Ignition. — Electric  Ignition  by 
Battery  and  Induction-Coil. — Ignition  by  Magnetos. — The  Piston. — 
Arrangement  of  the  Cylinder. — The  Frame. — Fly- Wheels. — Straight 
and  Curved  Spoke  Fly-Wheels. — The  Crank-Shaft. — Cams,  Rollers, 
etc.  —  Bearings.  —  Steadiness.  —  Governors. — Vertical  Engines.  — 
Power  of  an  Engine. — Automatic  Starting  .  .  .  .  .  .  21 


CHAPTER   III 
THE    INSTALLATION    OF   AN    ENGINE 

Location. — Gas-Pipes. — Dry  Meters. — Wet  Meters. — Anti-Pulsators, 
Bags,  Pressure-Regulators. — Precautions. — Air  Suction. — -Exhaust. 
— Legal  Authorization 69 

CHAPTER  IV 

FOUNDATION    AND    EXHAUST 

The  Foundation  Materials. — Vibration. — Air  Vibration,  etc. — Exhaust 
Noises 87 

xi 


xii  CONTENTS 

CHAPTER  V 

WATER    CIRCULATION 
Running  Water. — Water-Tanks. — Coolers      . 


CHAPTER  VI 

LUBRICATION 
Quality  of  Oils. — Types  of  Lubricators Ill 

CHAPTER  VII 

CONDITIONS    OF    PERFECT    OPERATION 

General  Care. — Lubrication. — Tightness  of  the  Cylinder. — Valve- 
Regrinding. — Bearings. — Crosshead. — Governor. — Joints. — Water 
Circulation. — Adjustment  .  .  .  .  .'.  .  .  .  .  .  121 

CHAPTER  VIII 

HOW  TO    START  AN  ENGINE.— PRELIMINARY  PRECAUTIONS 
Care  during  Operation. — Stopping  the  Engine 128 

'    CHAPTER   IX 

PERTURBATIONS    IN   THE    OPERATION   OF   ENGINES    AND 
THEIR   REMEDY 

Difficulties  in  Starting.^-Faulty  Compression. — Pressure  of  Water  in 
the  Cylinder. — Imperfect  Ignition. — Electric  Ignition,  by  Battery  or 
Magneto. — Premature  Ignition. — Untimely  Detonations. — Retarded 
Explosions. — Lost  Motion  in  Moving  Parts. — Overheated  Bearings. 
— Overheating  of  the  Cylinder. — Overheating  of  the  Piston. — Smoke 
arising  from  the  Cylinder. — Back  Pressure  to  the  Exhaust. — Sudden 
Stops  .  .  .  .  .  .  .  .  .  .  ...  .  .  134 


CONTENTS  xiii 


CHAPTER  X 

PRODUCER-GAS   ENGINES 

High    Compression.  —  Cooling.  —  Premature    Ignition.  —  The    Govern- 
ing of  Engines       ....       ......... 


CHAPTER  XI 

PRODUCER-GAS 

Street-Gas. — Composition  of  Producer-Gases. — Symptoms  of  Asphyxi- 
ation.— Gradual,  Rapid  Asphyxiation. — Slow,  Chronic  Asphyxiation. 
— First  Aid  in  Cases  of  Carbon  Monoxide  Poisoning. — Sylvester 
Method. — Pacini  Method. — Impurities  of  the  Gases  ....  165 


CHAPTER  XII 
PRESSURE    GAS-PRODUCERS 

Dowson  Producer.  —  Generators.  —  Air-Blast.  —  Blowers.  —  Fans.  — 
Compressors.  —  Exhausters.  —  Washing  and  Purifying.  —  Gas- 
Holder. — Lignite  and  Peat  Producers. — Distilling-Producers. — Pro- 
ducers Using  Wood  Waste,  Sawdust,  and  the  like. — Combustion- 
Generators. — Inverted  Combustion 174 


CHAPTER  XIII 
SUCTION    GAS-PRODUCERS 

Advantages. — Qualities  of  Fuel. — General  Arrangement. — Generator. 
— Cylindrical  Body.— Refractory  Lining. — Grate  and  Support  for  the 
Lining. — Ash-pit. — Charging- Box.  —  Slide-Valve.  —  Cock.  —  Feed- 
Hopper. — Connection  of  Parts. — Air  Supply. — Vaporizer. — Pre- 
heaters. — Internal  Vaporizers. — External  Vaporizers. — Tubular  Va- 
porizers.— Partition  Vaporizers. — Operation  of  the  Vaporizers. — Air- 
Heaters. — Dust-Collectors.— Cooler,  Washer,  Scrubber. — Purifying 
Apparatus.  —  Gas-Holders.  —  Drier.  —  Pipes.  —  Purifying-Brush.— 


xiv  CONTENTS 


Conditions  of  Perfect  Operation  of  Gas-Producers. — Workmanship 
and  System. — Generator. — Vaporizer. — Scrubber. — Assembling  the 
Plant. — Fuel. — How  to  Keep  the  Plant  in  Good  Condition. — Care 
of  the  Apparatus. — Starting  the  Fire  for  the  Gas-Producer. — Starting 
the  Engine. — Care  of  the  Generator  during  Operation. — Stoppages 
and  Cleaning 199 


CHAPTER  XIV 

OIL   AND   VOLATILE    HYDROCARBON    ENGINES 

Oil-Engines. — Volatile  Hydrocarbon  Engines. — Comparative  Costs. — 
Tests  of  High-Speed  Engines. — The  Manograph. — The  Continuous 
Explosion-Recorder  for  High-Speed  Engines. — Records  .  .  .  264 


CHAPTER  XV 
THE    SELECTION   OF   AN   ENGINE 

The  Duty  of  a  Consulting  Engineer. — Specifications. — Testing  the 
Plant. — Explosion-Recorder  for  Industrial  Engines. — Analysis  of 
the  Gases. — Witz  Calorimeter. — Maintenance  of  Plants. — Test  of 
Stockport  Gas-Engine  with  Dowson  Pressure  Gas-Producer. — Test 
of  a  Winterthur  Engine. — Test  of  a  Winterthur  Producer-Gas 
Engine. — Test  of  a  Deutz  Producer-Gas  Engine  and  Suction  Gas- 
Producer.— Test  of  a  aoo-H.P.  Deutz  Suction  Gas-Producer  and 
Engine 279 


CHAPTER  I 

MOTIVE  POWER — COST  OF  INSTALLATION 

THE  ease  with  which  a  gas-engine  can  be  installed, 
compared  with  a  steam-engine  is  self-evident.  In 
places  where  illuminating  gas  can  be  obtained  and 
where  less  than  10  to  15  horse-power  is  needed,  street- 
gas  is  ordinarily  employed.*  The  improvements  which 
have  very  recently  been  made  in  the  construction  of 
suction  gas-generators,  however,  would  seem  to  augur 
well  for  their  general  introduction  in  the  near  future, 
even  for  very  small  powers. 

The  installation  of  small  street-gas-engines  involves 
simply  the  making  of  the  necessary  connections  with 
gas  main  and  the  mounting  of  the  engine  on  a  small 
base. 

An  economical  steam-engine  of  equal  power  would 
necessitate  the  installation  of  a  boiler  and  its  setting, 
the  construction  of  a  smoke-stack,  and  other  acces- 
sories, while  the  engine  itself  would  require  a  firm 
base.  Without  exaggeration  it  may  be  asserted  that 
the  installation  of  a  steam-engine  and  of  its  boiler  re- 
quires five  times  as  much  time  and  trouble  as  the  in- 
stallation of  a  gas-engine  of  equal  power,  without 
considering  even  the  requirements  imposed  by  storing 
the  fuel  (Fig.  i).  Small  steam-engines  mounted  on 

*  Recent  improvements  made  in  suction  gas-producers  will  probably  lead 
to  the  wide  introduction  of  producer  gas  engines  even  for  small  power. 


i8      GAS-ENGINES    AND    PRODUCERS 


sa 


COST  OF  INSTALLATION  19 

• 

their  own  boilers,  or  portable  engines,  the  consumption 
of  which  is  generally  not  economical,  are  not  here 
taken  into  account. 

So  far  as  the  question  of  cost  is  concerned,  we  find 
that  a  15  to  20  horse-power  steam-engine  working  at 
a  pressure  of  90  pounds  and  having  a  speed  of  60  revo- 
lutions per  minute  would  cost  about  16^3  per  cent, 
more  than  a  15  horse-power  gas-engine,  with  its  anti- 
pulsators  and  other  accessories.  The  foundation  of 
the  steam-engine  would  likewise  cost  about  16^3  per 
cent,  more  than  that  of  the  gas-engine.  Furthermore 
the  installation  of  the  steam-engine  would  mean  the 
buying  of  piping,  of  a  boiler  of  100  pounds  pressure, 
and  of  firebrick,  and  the  erection  of  a  smoke-stack  hav- 
ing a  height  of  at  least  65  feet.  Beyond  a  little  excavat- 
ing for  the  engine-base  and  the  necessary  piping,  a 
gas-engine  imposes  no  additional  burdens.  It  may  be 
safely  accepted  that  the  steam-engine  of  the  power 
indicated  would  cost  approximately  45  per  cent,  more 
than  the  gas-engine  of  corresponding  power. 

The  cost. of  running  a  15  to  20  horse-power  steam- 
engine  is  likewise  considerably  greater  than  that  of 
running  a  gas-engine  of  the  same  size.  Considering 
the  fuel-consumption,  the  cost  of  the  lubricating  oil 
employed,  the  interest  on  the  capital  invested,  the  cost 
of  maintenance  and  repair,  and  the  salary  of  an  engi- 
neer, it  will  be  found  that  the  operation  of  the  steam- 
engine  is  more  expensive  by  about  23  per  cent. 

This  economical  advantage  of  the  gas  over  the  steam- 
engine  holds  good  for  higher  power  as  well,  and  be- 


20      GAS-ENGINES    AND    PRODUCERS 

comes  even  more  marked  when  producer-gas  is  used 
instead  of  street-gas.  Comparing,  for  example,  a  50 
horse-power  steam-engine  having  a  pressure  of  90 
pounds  and  a  speed  of  60  revolutions  per  minute,  with 
a  50  horse-power  producer-gas  engine,  and  considering 
in  the  case  of  the  steam-engine  the  cost  of  a  boiler  of 
suitable  size,  foundation,  firebrick,  smoke-stack,  etc., 
and  in  the  case  of  the  gas-engine  the  cost  of  the  pro- 
ducer, foundation,  and  the  like,  it  will  be  found  that 
the  installation  of  a  steam-engine  entails  an  expendi- 
ture 15  per  cent,  greater  than  in  the  case  of  the  pro- 
ducer-gas engine.  However,  the  cost  of  operating  and 
maintaining  the  steam-engine  of  50  horse-power  will 
be  40  per  cent,  greater  than  the  operation  and  main- 
tenance of  the  producer-gas  engine. 

From  the  foregoing  it  follows  that  from  15  to  20 
up  to  500  horse-power  the  engine  driven  by  producer- 
gas  has  considerably  the  advantage  over  the  steam- 
engine  in  first  cost  and  maintenance.  For  the  develop- 
ment of  horse-powers  greater  than  500,  the  employment 
of  compound  condensing-engines  and  engines  driven  by 
superheated  steam  considerably  reduces  the  consump- 
tion, and  the  difference  in  the  cost  of  running  a  steam- 
and  gas-engine  is  not  so  marked.  Still,  in  the  present 
state  of  the  art,  superheated  steam  installations  entail 
considerable  expense  for  their  maintenance  and  repair, 
thereby  lessening  their  practical  advantages  and  ren- 
dering their  use  rather  burdensome. 


CHAPTER  II 


THE  SELECTION   OF  AN   ENGINE 

EXPLOSION-ENGINES  are  of  many  types.  Gas-en- 
gines, of  the  four-cycle  type,  such  as  are  industrially 
employed,  will  here  be  principally  considered. 

The  Otto  Cycle. — The  term  "  four-cycle  "  motor,  or 
Otto  engine,  has  its  origin  in  the  manner  in  which  the 
engine  operates.  A  complete  cycle  comprises  four  dis- 
tinct periods  which  are  diagrammatically  reproduced 
in  the  accompanying  drawings. 

The  First  Period. — Suction:  The  piston  is  driven 
forward,  creating  a  vacuum  in  the  cylinder,  and  simul- 
taneously drawing  in  a.  certain  quantity  of  air  and  gas 

(Fig.  2). 


FIG.  2. — First  cycle:    Suction. 

The  Second  Period. — Compression:  The  piston  re- 
turns to  its  initial  position.  All  admission  and  exhaust 
valves  are  closed  (Fig.  3).  The  mixture  drawn  in 
during  the  first  period  is  compressed. 


21 


22      GAS-ENGINES    AND    PRODUCERS 


The  Third  Period.  —  Explosion  and  Expansion:  When 
the  piston  has  reached  the  end  of  its  return  stroke,  the 
compressed  mixture  is  ignited.  Explosion  takes  place 
at  the  dead  center.  The  expansion  of  the  gas  drives  the 
piston  forward  (Fig.  4). 


FIG.  3.-^Second  cycle:  Compression. 


FIG.  4. — Third  cycle:  Explosion  and  expansion. 

The  Fourth  Period. — Exhaust:  The  piston  returns 
a  second  time.  The  exhaust-valve  is  opened,  and  the 
products  of  combustion  are  discharged  (Fig.  5). 


— £te 


FIG.  5. — Fourth  cycle:  Exhaust. 

These  various  cycles  succeed  one  another,  passing 
through  the  same  phases  in  the  same  order. 


.  OBJECTIONS  TO  THE  SLIDE-VALVE      23 

Valve  Mechanism.— It  is  to  be  noted  that  in  mod- 
ern motors  valves  are  used  which  are  better  adapted  to 
the  peculiarities  of  explosion-engines  than  were  the 
old  slide-valves  used  when  the  Otto  engine  was  first 
introduced.  The  slide-valve  may  now  be  considered 
as  an  antiquated  distributing  device  with  which  it  is 
impossible  to  obtain  a  low  consumption. 

In  old-time  gas-engines  rather  low  compressions  were 
used.  Consequently  a  very  low  explosive  power  of  the 
gaseous  mixture,  and  low  temperatures  were  obtained. 
The  slide-valves  were  held  to  their  seats  by  the  pres- 
sure of  external  springs,  and  were  generously  lubri- 
cated. Under  these  conditions  they  operated  regularly. 
Nowadays,  the  necessity  of  using  gas-engines  which  are 
really  economical  has  led  to  the  use  of  high  compres- 
sions with  the  result  that  powerful  explosions  and  high 
temperatures  are  obtained.  Under  these  conditions 
slide-valves  would  work  poorly.  They  would  not  be 
sufficiently  tight.  To  lubricate  them  would  be  difficult 
and  ineffective.  Furthermore,  large  engines  are  widely 
used  in  actual  practice,  and  with  these  motors  the  fric- 
tional  resistance  of  large  slide-valves,  moving  on  exten- 
sive surfaces  would  be  considerable  and  would  appre- 
ciably reduce  the  amount  of  useful  work  performed. 

By  reason  of  its  peculiar  operation,  the  slide-valve 
is  objectionable,  the  gases  being  throttled  at  the  time  of 
their  admission  and  discharge.  As  a  result  of  these  ob- 
jections there  are  losses  in  the  charge;  and  obnoxious 
counter-pressures  occur.  The  necessity  of  using  ele- 
ments simple  in  their  operation  and  free  from  the  ob- 


24      GAS-ENGINES    AND    PRODUCERS 

jections  which  have  been  mentioned,  has  naturally  led 
to  the  adoption  of  the  present  valve.  This  valve  is  used 
both  for  the  suction  of  the  gas  and  of  the  air,  as  well  as 
for  the  exhaust,  with  the  result  that  either  of  these  two 
essential  phases  in  the  operation  of  the  motor  can  be 
independently  controlled.  The  valves  offer  the  follow- 
ing advantages :  Their  tightness  increases  with  the  pres- 
sure, since  they  always  open  toward  the  interior  of  the 
cylinder  (Fig.  6).  They  have  no  rubbing  surfaces, 


FIG.  6. — Modern  valve  mechanism. 

and  need  not,  therefore,  be  lubricated.  Their  opening 
is  controlled  by  levers  provided  with  quick-acting 
cams;  and  their  closure  is  effected  by  coiled  springs 
almost  instantaneous  in  their  action  (Fig.  7).  Each 
valve,  depending  upon  the  purpose  for  which  it  is  used, 
can  be  mounted  in  that  part  of  the  cylinder  best  suited 
for  its  particular  function.  The  types  of  valved  motors 
now  used  are  many  and  various.  In  order  to  attain 


REQUISITES  OF  VALVES  25 

I 

economy  in  consumption  and  regularity  in  operation 
they  should  meet  certain  essential  requirements  which 
will  here  be  reviewed. 

Apart  from  proportioning  the  areas  properly  and 
from  providing  a  suitable  means  of  operation,  it  is  in- 
dispensable that  the  valves  should  be  readily  accessible. 
Indeed,  the  valves  should  be  regularly  examined, 


FIG.  7. — Controlling  mechanism  of  valve. 

cleaned  and  ground.     It  follows  that  it  should  be  pos- 
sible to  take  them  apart  easily  and  quickly. 

It  is  necessary  that  the  exhaust-valve  be  well  cooled; 
otherwise  the  valve,  exposed  as  it  is  to  high  tempera- 
tures, will  suffer  derangement  and  may  cause  leakage. 
The  water-jacket  should,  therefore,  surround  the  seat 
of  the  exhaust-valve,  care  being  taken  that  the  cooling 
water  be  admitted  as  near  to  it  as  possible  (Fig.  8). 
The  motor  should  control  the  air-let  valve  or  that  of 
the  gaseous  mixture.  Hence  these  valves  should  not 


26      GAS-ENGINES    AND    PRODUCERS 

be  actuated  simply  by  springs,  because  springs  are  apt 
to  move  under  the  influence  of  the  vacuum  produced 
by  suction. 


FIG.  8.— Water-jacketed  valve. 

The  mixture  of  gas  and  air  should  not  be  admitted 
into  the  cylinder  at  too  low  a  pressure;  otherwise  the 
weight  of  the  mixture  admitted  would  be  lower  than  it 


REQUISITES   OF  VALVES  27 


• 


ought  to  be,  inasmuch  as  under  these  conditions  the 
valve  will  be  opened  too  tardily  and  closed  prema- 
turely. At  the  beginnings  well  as  at  the  end  of  its 
stroke  the  linear  velocity  of  the  piston  is  quite  inade- 
quate to  create  a  vacuum  sufficient  to  overcome  the  re- 
sistance of  the  spring.  It  is,  therefore,  generally  the 
practice  separately  to  control  the  opening  or  closing  of 
the  one  or  the  other  valve  (gas-valve  or  mixture-valve) . 
Consequently  these  valves  must  be  actuated  independ- 
ently of  each  other.  Nowadays  they  are  mechanically 
controlled  almost  exclusively, — a  method  which  is  ad- 
vocated by  well-known  designers  for  industrial  motors 
in  particular.  Valves  which  are  not  actuated  in  this 
manner  (free  valves)  have  only  the  advantage  of  sim- 
plicity of  operation.  Nevertheless,  this  arrangement 
is  still  to  be  found  in  certain  oil  and  benzine  engines, 
notably  in  automobile-motors.  In  these  motors  it  is 
necessary  to  atomize  the  liquid  fuel  by  means  of  aspired 
air,  in  order  to  produce  an  explosive,  gaseous  mixture. 

Ignition. — In  the  development  of  the  gas-engine,  the 
incandescent  tube  and  the  electric  spark  have  taken  the 
place  of  the  obsolete  naked  flame.  The  last-mentioned 
mode  of  exploding  the  gaseous  mixture  will  not,  there- 
fore, be  discussed. 

The  hot  tube  of  porcelain  or  of  metal  has  the  in- 
disputable merit  of  regularity  of  operation.  The  meth- 
ods by  which  this  operation  is  made  as  perfect  as 
possible  are  many.  Since  certainty  of  ignition  is  ob- 
tained by  means  of  the  tube,  it  is  important  to  time  the 
ignition,  so  that  it  shall  occur  exactly  at  the  moment 


28      GAS-ENGINES    AND    PRODUCERS 

when  the  piston  is  at  the  dead  center.  It  has  been 
previously  stated  that  premature  or  belated  ignition  of 
the  explosive  mixture  appreciably  lessens  the  amount 
of  useful  work  performed  by  the  expansion  of  the  gas. 
If  ignition  occur  too  soon,  the  mixture  will  be  exploded 
before  the  piston  has  reached  the  dead  center  on  its 
return  stroke.  As  a  result,  the  piston  must  overcome  a 
considerable  resistance  due  to  the  premature  explosion 
and  the  consequent  pressure.  Furthermore,  by  reason 
of  the  high  temperature  of  explosion,  the  gaseous  prod- 
ucts are  very  rapidly  cooled.  This  rapid  cooling  causes 
a  sudden  drop  in  the  pressure;  and  since  a  certain  inter- 
val elapses  between  the  moment  of  explosion  and  the 
moment  when  the  piston  starts  on  its  forward  stroke, 
the  useful  motive  effort  is  the  more  diminished  as  the 
ignition  is  more  premature. 

Incandescent  Tubes. — In  Figs.  9  and  10  two  systems 
most  commonly  used  are  illustrated.  In  these  two  ar- 
rangements, in  which  no  valve  is  used,  the  length  or 
height  to  which  the  tube  is  heated  by  the  outer  flame  is 
so  controlled  that  the  gaseous  mixture,  which  has  been 
driven  into  the  tube  after  compression,  reaches  the 
incandescent  zone  as  nearly  as  possible  at  the  exact 
moment  when  ignition  and  explosion  should  take  place. 
The  temperature  of  the  flame  of  the  burner,  the  rich- 
ness of  the  gaseous  mixture,  and  other  circumstances, 
however,  have  a  marked  influence  on  the  time  of  igni- 
tion, so  that  the  mixture  is  never  fired  at  the  exact 
moment  mentioned. 

These   considerations   lead   to   the   conclusion   that 


THE   INCANDESCENT  TUBE 


29 


motors  in  which  the  mixture  is  exploded  by  hot  tubes 
provided  with  an  ignition-valve  are  preferable  to  valve- 
less  tubes.  By  the  use  of  a  special  valve,  positively 
controlled  by  the  motor  itself,  the  chances  of  untimely 
ignition  are  lessened,  because  it  is  necessary  simply  to 
regulate  the  temperature  and  the  position  of  the  tube 
in  order  that  ignition  may  be  surely  effected  imme- 


FIGS.  9-10. — Valveless  hot  tubes. 

diately  upon  the  opening  of  the  valve,  at  the  very  mo- 
ment the  cylinder  gases  come  into  contact  with  the  in- 
candescent portion  of  the  tube  (Fig.  1 1 ) .  Many  manu- 

* 

facturers,  however,  do  not  employ  the  ignition-valve  on 
motors  of  less  than  15  to  20  horse-power,  chiefly  because 
of  the  cheaper  construction.  The  total  consumption 


3o      GAS-ENGINES    AND    PRODUCERS 

is  of  less  moment  in  a  motor  of  small  than  of  great 
power,  and  the  loss  due  to  the  lack  of  an  ignition-valve 
not  so  marked.  In  a  high-power  engine,  premature  ex- 
plosion may  be  the  cause  of  the  breaking  of  a  vital 
part,  such  as  the  piston-rod  or  the  crank-shaft.  For 
this  reason,  a  valve  is  indispensable  for  engines  of  more 
than  2  oto  25  horse-power.  A  breakage  of  this  kind  is. 
less  to  be  feared  in  a  small  motor,  where  the  parts  are 


FIG.  ii. — Ignition -tube  with  valve. 

comparatively  stout.  The  gas  consumption  of  a  well- 
designed  burner  does  not  exceed  from  3.5  to  5  cubic 
feet  per  hour. 

Electric  Ignition. — Electric  ignition  consists  in  pro- 
ducing a  spark  in  the  explosion-chamber  of  the  engine. 
The  nicety  with  which  it  can  be  controlled  gives  it  an 
undeniable  advantage  over  the  hot  tube.  But  the  ob- 


ELECTRIC   IGNITION 


31 


jection  has  been  raised,  perhaps  with  some  force,  that 
it  entails  certain  complications  in  installing  the  engine. 
Its  opponents  even  assert  that  the  power  and  the  rapid- 
ity of  the  deflagration  of  the  explosive  mixture  are 
greater  with  hot-tube  ignition.  This  reason  may  have 
caused  the  hot-tube  system  to  prevail  in  England, 
where  manufacturers  of  gas-engines  are  very  numerous 
and  not  lacking  in  experience. 

Electric  ignition  is  effected  in  gas-engines  by  means 
of  a  battery  and  spark-coil,  or  by  means  of  a  small  mag- 
neto machine  which  mechanically  produces  a  current- 
breaking  spark. 

Electric  Ignition  by  Battery  and  Induction-Coil.— 
The  first  system  is  the  cheaper;  but  it  exacts  the  most 


FIG.  12. — Electric  ignition  by  spark-coil  and  battery. 

painstaking  care  in  maintaining  the  parts  in  proper 
working  condition.  It  comprises  three  essential  ele- 
ments— a  battery,  a  coil,  and  a  spark-plug  (Fig.  12). 
The  battery  may  be  a  storage-battery,  which  must,  con- 
sequently, be  recharged  from  time  to  time;  or  it  may  be 


32 


GAS-ENGINES    AND    PRODUCERS 


a  primary  battery  which  must  be  frequently  renewed 
and  carefully  cleaned.  The  induction-coil  is  fitted  with 
a  trembler  or  interrupter,  which  easily  gets  out  of  order 
and  which  must  be  regulated  with  considerable  accu- 
racy. The  spark-plug  is  a  particularly  delicate  part, 
subject  to  many  possible  accidents.  The  porcelain  of 
which  it  is  made  is  liable  to  crack.  It  is  hard  to  obtain 


FIG.  13. — Spark-plug. 

absolutely  perfect  insulation ;  for  the  terminals  deterio- 
rate as  they  become  overheated,  break,  or  become  foul 
(Fig.  13).  In  oil-engines,  especially,  soot  is  rapidly 
deposited  on  the  terminals,  so  that  no  spark  can  be  pro- 
duced. In  benzine  or  naphtha  motors,  such  an  accident 
is  less  likely  to  happen.  In  automobile-motors,  how- 
ever, the  spark-plug  only  too  often  fails  to  perform  its 
function.  The  one  remedy  for  these  evils  is  to  be  found 


IGNITION   BY   MAGNETO 


33 


in  the  most  painstaking  care  of  the  spark-plug  and  of 
the  other  elements  of  the  ignition  system. 

Ignition  by  Magnetos. — Magneto  apparatus,  on  the 
other  hand,  are  noteworthy  for  the  regularity  of  their 
operation.  They  may  be  used  for  several  years  with- 


FIG.  14. — Magneto  ignition  apparatus. 

out  being  remagnetized,  and  require  no  exceptional 
care.  Magneto  ignition  devices  are  mechanically  ac- 
tuated, the  necessary  displacement  of  the  coil  being 
effected  by  means  of  a  cam  carried  on  a  shaft  turning 
with  half  the  motor  speed  (Figs.  14  and  15).  At  the 
moment  when  it  is  released  by  the  cam,  the  coil  is  sud- 


34      GAS-ENGINES    AND    PRODUCERS 

denly  returned  to  its  initial  position  by  means  of  a 
spring.  This  rapid  movement  generates  a  current  that 
passes  through  terminals,  which  are  arranged  within 
the  cylinder  and  which  are  immediately  separated  by 
mechanical  means.  Thus  a  much  hotter  circuit-break- 


FIG.  15. — General  view  and  details  of  a  magneto  ignition  apparatus. 

ing  spark  is  produced,  which  is  very  much  more 
energetic  than  that  of  a  battery  and  induction-coil,  and 
which  surely  ignites  the  gaseous  mixture  in  the  cylin- 
der. The  terminals  are  generally  of  steel,  sometimes 
pointed  with  nickel  or  platinum  (Fig.  16).  The  only 
precaution  to  be  observed  is  the.  exclusion  of  moisture 


MAGNETO  IGNITION 


35 


and  occasional  cleaning.     For  engines  driven  by  pro- 
ducer-gas magneto-igniters  are  preferable  to  cells  and 


FIG.  16. — Contacts  of  a  magneto-igniter. 

batteries.     In  general,  electrical  ignition  is  to  be  rec- 
ommended for  high-pressure  engines. 

In  order  to  explain  more  clearly  modern  methods  of 
ignition  a  diagram  is  presented,  showing  an  electric 


FIG.  17. — Device  for  regulating  the  moment  of  ignition. 

magneto-igniter  applied  to  the  cylinder-head  of  a 
Winterthur  motor,  and  also  a  sectional  view  of  the 
member  varying  the  make-and-break  contacts  which 


36      GAS-ENGINES    AND    PRODUCERS 

are  mounted  in  the  explosion-chamber  (Figs.  18  and 
19). 

i.  The  magneto  A  consists  of  horseshoe-magnets, 
between  the  poles  of  which  the  armature  rotates.  At 
its  conically  turned  end,  the  armature-shaft  carries  an 
arm  #,  held  in  place  by  a  nut. 


FIG.  1 8. — Winterthur  electric  ignition  system. 

2.  The  igniter  C  is  a  casting  secured  to  the  cylinder- 
head  by  a  movable  strap  and  provided  with  two  axes 
D  and  Af,  of  which  the  one,  Z),  made  of  bronze,  is 
movable,  and  is  fitted  with  a  small  interior  contact- 
hammer,  a  percussion-lever,  and  an  exterior  recoil- 
spring;  the  other,  M,  is  fixed,  insulated,  and  arranged 


A   MODERN    MAGNETO-IGNITER         37 

9 
to  receive  the  current  from  the  magneto  A,  by  means 

of  an  insulated  copper  wire  E. 

3.  The  spring  F  comprises  two  continuous  coils  con- 
tained in  a  brass  casing,  and  actuating  a  steel  striking 
or  percussion-pin. 

4.  The  controlling  devices  of  the  magneto  include  a 
stem  or  rod  G,  slidable  in  a  guide  H,  provided  with  a 


FIG.  19. — Contacts  of  the  Winterthur  system. 

safety  spring  and  mounted  on  an  eccentric  spindle,  the 
position  of  which  can  be  varied  by  means  of  a  regulat- 
ing-lever (/) .  The  rod  is  operated  from  the  dis- 
tributing-shaft, on  the  conical  end  of  which  a  cam  J 
carrying  a  spindle  is  secured. 

Regulation  of  the  Magneto. — The  position  assumed 
by  the  armature  when  at  rest  is  a  matter  of  importance 
in  obtaining  a  good  spark  on  breaking  the  circuit.  The 
marks  on  the  armature  should  be  noted.  The  position 


38      GAS-ENGINES    AND    PRODUCERS 

of  the  armature  may  be  experimentally  varied,  in  order 
to  obtain  a  spark  of  maximum  intensity,  by  changing 
the  position  of  the  arm  B  on  the  armature-shaft. 

Control  of  the  Magneto. — The  controlling  gear 
should  enable  the  armature  to  oscillate  from  20  to  25 
degrees.  The  time  at  which  the  breaking  of  the  circuit 
is  effected  can  be  regulated  by  shifting  the  handle  (/). 
In  starting  the  engine,  the  circuit  can  be  broken  with 
a  slight  retardation,  which  is  lessened  as  the  engine 
attains  its  normal  speed. 

Igniter. — It  is  advisable  that  there  should  be  a  play 
of  y<2,  mm.  (0.0196  in.)  between  the  lever  Z  when  at 
rest  and  the  striking-pin.  The  axis  D  of  the  circuit- 
breaking  device  should  be  easily  movable;  and  the 
hammer  which  it  carries  at  its  end  toward  the  interior 
of  the  cylinder  should  be  in  perfect  contact  with  the 
stationary  spindle  Af,  which  is  electrically  insulated. 
This  spindle  M  should  be  well  enclosed,  in  order  to 
prevent  any  leakage  that  might  cause  a  deterioration  of 
the  insulating  material. 

The  subject  of  ignition  is  of  such  extreme  impor- 
tance that  the  author  will  recur  to  it  from  time  to  time 
in  the  various  chapters  of  this  book.  Too  much  stress 
cannot  be  laid  upon  proper  timing;  otherwise  there 
will  be  a  needless  waste  of  power.  Cleanliness  is  a 
point  that  must  be  observed  scrupulously;  for  spark- 
plugs are  apt  to  foul  only  too  readily,  with  the  result 
that  short-circuits  and  misfires  are  apt  to  occur.  In 
oil  and  volatile  hydrocarbon  engines  the  tendency  to 
fouling  is  particularly  noticeable.  In  the  chapter  de- 


THE    PISTON 


39 


voted  to  these  forms  of  motors  the  author  has  dwelt 
upon  the  precautions  that  should  be  taken  to  forestall  a 
possible  derangement  of  the  ignition  apparatus.  As  a 
general  rule  the  ignition  apparatus  installed  by  trust- 
worthy manufacturers  will  be  found  best  suited  for  the 
requirements  of  the  engine. 

The  apparatus  should  be  fitted  with  a  device  by 
which  the  ignition  can  be  duly  timed  by  hand  during 
operation  (Fig.  17). 

The  Piston. — Coming,  as  it  does,  continually  in  con- 
tact with  the  ignited  gases,  the  piston  is  gradually 


FIG.  20. — Design  of  the  piston. 

heated  to  a  high  temperature.  The  rear  face  of  the 
piston  should  preferably  be  plane.  Curved  surfaces 
are  not  to  be  recommended  because  they  cool  off 
badly.  Likewise,  faces  having  either  inserted  parts 
or  bolt-heads  are  to  be  avoided,  since  they  are  liable  to 
become  red-hot  and  to  ignite  the  mixture  prematurely 
(Fig.  20). 


4o      GAS-ENGINES    AND    PRODUCERS 

Among  the  parts  of  the  piston  which  rapidly  wear 
away  because  constant  lubrication  is  difficult,  is  the 
connection  with  the  piston-rod  (Fig.  21).  It  is  im- 
portant that  the  bearing  at  the  piston-pin  be  formed  of 
two  parts  which  can  be  adjusted  to  take  up  the  wear. 
The  pin  itself  should  be  of  case-hardened  steel.  For 
large  engines,  some  manufacturers  have  apparently 
abandoned  the  practice  of  locking  the  pin,  by  set-screws, 
in  flanges  cast  in  one  piece  with  the  piston.  Indeed, 
the  piston  is  often  fractured  by  reason  of  the  expansion 
of  the  pins  thus  held  on  two  sides.  It  seems  advisable 


FIG.  21. — Piston  with  lubricated  pin. 

to  secure  the  pin  by  means  of  a  single  screw  in  one  of 
the  flanges,  fitting  it  by  pressure  against  the  opposite 
boss.  The  use  of  wedges  or  of  clamping-screws,  in- 
troduced from  without  the  piston  to  hold  the  pin, 
should  be  avoided.  It  may  happen  that  the  wedges 
will  be  loosened,  will  move  out,  and  will  grind  the 
cylinder,  causing  injuries  that  cannot  be  detected  before 
it  is  too  late.  The  strength  of  the  piston-pin  should  be 
so  calculated  that  the  pressure  per  square  inch  of  pro- 
jected surface  does  not  exceed  1,500  to  2,850  pounds 
per  square  inch.  It  should  be  borne  in  mind  that  the 


PISTON-RINGS  41 

initial  pressure  of  the  explosion  is  often  equal  to  400  to 
425  pounds  per  square  inch.  Some  manufacturers 
mount  the  pin  as  far  to  the  back  of  the  piston  as  possi- 
ble, so  as  to  bring  it  nearer  the  point  of  application  of 
the  motive  force  of  the  explosion.  Other  manufac- 
turers, on  the  other  hand,  mount  the  pin  toward  the 
front  of  the  piston.  No  great  objection  can  be  raised 
against  either  method.  In  the  former  case  the  position 
of  the  rings  will  limit  that  of  the  pin. 

The  number  of  these  rings  ought  not  to  be  less  than 
four  or  five,  arranged  at  the  rear  of  the  piston.  It  is 
to  be  observed  that  makers  of  good  engines  use  as  many 
as  8  to  10  rings  in  the  pistons  of  fair-sized  motors. 

Piston-rings  of  gray  pig-iron  can  be  adjusted  with 
the  greatest  nicety  in  such  a  manner  that,  by  means 
of  tongues  fitting  in  their  grooves,  they  are  held  from 
turning  in  the  latter,  whereby  their  openings  are  pre- 
vented from  registering  and  allowing  the  passage  of 
gas.  As  a  general  rule,  a  large  number  of  rings 
may  be  considered  a  distinguishing  feature  of  a  well- 
built  engine.  In  order  to  prevent  a  too  rapid  wear  of 
the  cylinder,  several  German  manufacturers  finish  off 
the  front  of  the  piston  with  bronze  or  anti-friction 
metal  in  engines  of  more  than  40  to  50  horse-power.  It 
is  to  be  observed,  however,  that  this  expedient  is  not 
applicable  to  motors  the  cylinders  of  which  are  com- 
paratively cold;  otherwise  the  bronze  or  anti-friction 
metal  will  deteriorate. 

Arrangement  of  the  Cylinder. — The  cylinder  shell 
or  liner,  in  which  the  piston  travels,  and  the  water- 


42      GAS-ENGINES    AND    PRODUCERS 

jacket  should  preferably  be  made  in  separate  pieces  and 
not  cast  of  the  same  metal,  in  order  to  permit  a  free 
expansion  (Figs.  22  and  23).  If  for  want  of  care  or 


FIG.  22. — Head,  jacket  and  liner  of  cylinder,  cast  in  one  piece. 

of  proper  lubrication,  which  frequently  occurs  in  gas- 
engines,  the  cylinder  should  be  injured  by  grinding, 
it  can  be  easily  renewed,  without  the  loss  of  all  the  con- 
necting parts. 

For  the  same   reason,   the  cylinder  and  its  casing 


FIG.  23. — Cylinder  with  independent  liner  and  head. 

should  be  independent  of  the  frame.  In  many  horizon- 
tal engines,  the  cylinders  overhang  the  frame  through- 
out the  entire  length,  by  reason  of  the  joining  of  their 


FAULTS  OF  SINGLE-ACTING  ENGINES    43 

• 

front  portions  with  the  frames.  Although  such  a  con- 
struction is  attended  with  no  serious  consequences  in 
small  engines,  nevertheless  in  large  engines  it  is  ex- 
ceedingly harmful.  Indeed,  in  most  modern  single- 
acting  engines,  the  pistons  are  directly  connected  with 
the  crank-shaft  by  the  piston-rod,  without  any  inter- 
mediate connecting-rod  or  cross-head.  The  vertical  re- 


FIG.  24. — Single-acting  engines. 

action  of  the  motive  effort  on  the  piston  is,  therefore, 
taken  up  entirely  by  the  thrust  of  the  cylinder,  which 
is  also  vertical  (Fig.  24).  This  thrust,  acting  against 
an  unsupported  part,  may  cause  fractures;  at  any  rate, 
it  entails  a  rapid  deterioration  of  the  cylinder  joint. 

The  Frame. — Gas-engines  driven  as  they  are,  by  ex- 
plosions, giving  rise  to  shocks  and  blows,  should  be 
built  with  frames,  heavy,  substantial,  and  broad-based, 


44      GAS-ENGINES    AND    PRODUCERS 

so  as  to  rest  solidly  on  the  ground.  This  essential  con- 
dition is  often  fulfilled  at  the  cost  of  the  engine's  ap- 
pearance; but  appearance  will  be  willingly  sacrificed 
to  meet  one  of  the  requirements  of  perfect  operation. 
For  engines  of  more  than  8  to  10  horse-power,  frames 
should  be  employed  which  can  be  secured  to  the 
masonry  foundation  without  a  separate  pedestal  or  base. 
Some  manufacturers,  for  the  purpose  of  lightening  the 
frame,  attach  but  little  importance  to  the  foundation 


FIG.  25. — Engine  with  inclined  bearings. 

and  to  strength  of  construction,  and  employ  the  design 
illustrated  in  place  of  the  crank-shaft  bearing  (Fig. 
25)  ;  others,  in  order  to  facilitate  the  adjusting  of  the 
connecting-rod  bearings,  prefer  the  second  form  (Fig. 
26).  It  is  evident  that,  in  the  first  case,  a  part  of  the 
effort  produced  by  the  explosion  reacts  on  the  upper 
portion  of  the  connecting-rod  bearing,  on  the  cap  of 
the  crank-shaft  bearing,  and  consequently  on  the  fas- 
tening-bolts. In  the  second  case,  if  the  adjustment 
be  not  very  carefully  made,  or  if  the  rubbing  surfaces 
are  insufficient,  the  entire  thrust  due  to  the  explosion 


CRANK-SHAFT    BEARINGS 


45 


will  be  received  by  the  meeting  parts  of  the  two  bush- 
ings, thus  injuring  them  and  causing  a  more  rapid 
wear.  In  the  construction  of  large  engines,  some  manu- 


FIG.  26. — Engine  with  straight  bearings. 

facturers  take  the  precaution  of  forming  the  connect- 
ing-rod bearings  of  four  parts,  adjustable  to  take  up  the 
wear,  so  that  the  effort  is  exerted  against  the  parts  dis- 
posed at  right  angles  to  each  other.  A  form  that  seems 
rational  is  that  shown  in  Fig.  27,  in  which  the  reaction 


FIG.  27. — Engine  with  correctly  designed  bearings. 

of  the  thrust  is  taken  up  by  the  lower  bearing,  rigidly 
supported  by  the  braced  frame,  in  the  direction  opp'o- 
site  to  that  of  the  explosive  effort. 


46      GAS-ENGINES    AND    PRODUCERS 

The  sum  of  the  projecting  surfaces  of  the  two  bear- 
ings should  be  so  calculated  that  a  maximum  explosive 
pressure  of  405  to  425  pounds  per  square  inch  will  not 
subject  the  bearings  to  a  pressure  higher  than  425  to 
550  pounds  per  square  inch. 

Fly-Wheels.— In  gas-engines  particularly,  the  fly- 
wheel should  be  secured  to  the  crank-shaft  with  the  ut- 
most care.  It  should  be  mounted  as  near  as  possible 
to  the  bearings;  otherwise  the  alinement  of  the  shaft 
will  be  destroyed  and  its  strength  impaired.  If  the  fly- 
wheel be  fastened  by  means  of  a  key  or  wedge  having 
a  projecting  head,  it  is  advisable  to  cover  the  end  of  the 
shaft  by  a  movable  sleeve.  The  fly-wheel  should  run 
absolutely  true  and  straight  even  if  the  explosion  be 
premature.  In  well-built  engines  the  fly-wheels  are 
lined  up  and  shaped  to  the  rim.  The  periphery  is 
slightly  rounded  in  order  the  better  to  guide  the  belt 
\vhen  applied  to  the  wheel. 

Furthermore,  fly-wheels  should  be  nicely  balanced; 
those  are  to  be  preferred  which  have  no  counter- weights 
cast  or  fastened  to  the  hub,  the  spokes,  or  the  rim. 

The  system  of  balancing  the  engine  by  means  of  two 
fly-wheels,  mounted  on  opposite  sides,  is  used  chiefly 
for  the  purpose  of  equalizing  the  inertia  effects.  Spe- 
cial engines,  employed  for  driving  dynamos,  and  even 
industrial  engines  of  high  power,  are  preferably  fitted 
with  but  a  single  fly-wheel,  with  an  outer  bearing,  since 
they  more  readily  counteract  the  cyclic  irregularities  or 
variations  of  speed  occurring  in  a  single  revolution 
(Fig.  28).  If  in  this  case  a  pulley  be  provided,  it 


FLY-WHEELS 


47 


J 


=  S  -V^  Z?=   ~ -•   "  rC 


<U 

C 

'5b 

0) 


I 


48      GAS-ENGINES    AND    PRODUCERS 

should  be  mounted  between  the  engine  and  the  outer 
bearing.  The  following  advantages  may  be  cited  in 
favor  of  the  single  fly-wheel,  particularly  in  the  case  of 
dynamo-driving  engines : 

1.  The  single  fly-wheel  permits  a  more  ready  access 
to  the  parts  to  be  examined. 

2.  It  involves  the  employment  of  a  third  bearing, 
thus  avoiding  the  overhang  caused  by  two  ordinary  fly- 
wheels. 

3.  It  avoids  the  torsional  strain  to  which  the  two- 
wheel  crank  is  subjected  when  starting,  stopping,  and 
changing  the  load,  the  peripheral  resistance  varying 
in  one  of  the  fly-wheels,  while  the  other  is  subjected  to 
a  strain  in  the  opposite  direction  on  account  of  the 
inertia. 

4.  Two  fly-wheels,  keyed  as  they  are  to  projecting 
ends  of  the  shaft,  will  be  so  affected  at  the  rims  by  the 
explosions  that  the  belts  will  shake. 

The  third  bearing  which  characterizes  the  single- 
fly-wheel  system,  is  but  an  independent  support,  rest- 
ing solidly  on  the  masonry  bed  of  the  engine.  The 
bearing  with  its  independent  support  is  sufficiently 
rigid,  and  is  not  subjected  to  any  stress  from  the  crank 
at  the  moment  of  explosion,  the  reaction  of  the  crank 
affecting  only  the  frame  bearings.  With  such  fly- 
wheels, reputable  firms  guarantee  a  cyclic  regularity 
which  compares  favorably  with  that  of  the  best  steam- 
engines.  For  a  duty  varying  from  a  third  of  the  load  to 
the  maximum  load,  these  engines,  when  driving  direct- 
current  dynamos  for  directly  supplying  an  electric- 


FLY-WHEEL    SPOKES 


49 


light  circuit,  will  insure  perfect  steadiness  of  the  light; 
and  the  effectually  aperiodic  measuring  instruments 
will  not  indicate  fluctuations  greater  than  2  to  3  per 
cent,  of  the  tension  or  intensity  of  the  current.  The 
coefficient  of  the  variations  in  the  speed  of  a  single  rev- 
olution will  thus  be  not  far  from  -^Q. 
Straight  and  Curved  Spoke  Fly-Wheels.— The 


FIG.  29. — Curved  spoke  fly-wheel. 

spokes  of  fly-wheels  are  either  straight  or  curved.  In 
assembling  the  motor  parts  it  too  often  occurs  that 
curved  spoke  fly-wheels  are  mounted  with  utter  dis- 
regard of  the  direction  in  which  they  are  to  turn.  It 
is  important  that  curved  spokes  should  be  subjected  to 
compression  and  not  to  traction.  Hence  the  fly-wheels 


5o      GAS-ENGINES    AND    PRODUCERS 


should  be  so  mounted  that  the  concave  portions  of  the 
spokes  travel  in  the  direction  of  rotation,  as  shown  in 
the  accompanying  diagram  (Fig.  29).  If  a  single  fly- 
wheel be  employed  on  an  engine  of  the  type  in  which 


FIG.  30. — Forged  crank -shafts. 

the  speed  is  governed  by  the  "  hit-and-miss  "  system, 
the  fly-wheel  should  be  extra  heavy  to  counteract  the  ir- 
regularities of  the  motive  impulses  when  the  engine  is 
not  working  at  its  full  load,  or  in  other  words,  when  no 
explosion  takes  place  at  every  cycle. 

The  Crank-Shaft.— The  crank-shaft  should  be  made 
of  the  best  mild  steel.    Those  shafts  are  to  be  preferred 


_ — — — — 

o 


FIG.  31. — Correct  design  of  crank-shaft. 

the  cranks  of  which  are  not  forged  on  (Fig.  30),  but 
cut  out  of  the  mass  of  metal;  furthermore,  the  brackets 
or  supports  should  be  planed  and  shaped  so  that  they 
are  square  in  cross-section. 


CAMS  AND   ROLLERS 


51 


Such  a  design  involves  fine  workmanship  and  speaks 
well  for  the  construction  of  the  whole  engine.  More- 
over, it  enables  the  bearings  to  be  brought  nearer  each 
other,  reduces  to  a  minimum  that  part  of  the  crank- 
shaft which  may  be  considered  the  weakest,  and  per- 
mits a  rational  and  exact  counterbalancing  of  the  mov- 
ing parts,  such  as  the  crank  and  the  end  of  the  connect- 
ing-rod. The  best  manufacturers  have  adopted  the 
method  of  fastening  to  the  cranks  balancing  weights 
secured  to  the  brackets,  especially  for  high-speed  en- 


IT 


FIG.  32. — Crank -shaft  with  balancing  weight. 

gines  or  for  engines  of  high  power.  The  projecting 
surface  of  the  crank-pin  should,  as  a  rule,  be  calculated 
for  a  pressure  of  1,400  pounds  per  square  inch. 

Cams,  Rollers,  etc. — The  cams,  rollers,  thrust-bear- 
ings, as  well  as  the  piston-pin  in  particular,  should  be 
made  of  good  steel,  case-hardened  to  a  depth  of  at  least 
.08  of  an  inch.  Their  hardness  and  the  degree  of 
cementation  may  be  tested  by  means  of  a  file.-  This  is 
the  method  followed  by  the  best  manufacturers. 

Bearings. — All  the  bearings  and  all  guides  should 
be  adjustable  to  take  up  the  wear.  They  are  usually 
made  of  bronze  or  of  the  best  anti-friction  metal. 


52      GAS-ENGINES    AND    PRODUCERS 

Steadiness. — The  steadiness  of  engines  may  be  con- 
sidered from  two  different  standpoints. 

I.  Variation  of  the  Number  of  Revolutions  at  Dif- 
ferent Loads. — This  depends  chiefly  on  the  sensitive- 
ness of  the  governor,  which  should  be  of  the  "  inertia  " 
or  of  the  "  ball  "  (or  centrifugal)  type.  The  first  form 
is  rarely  employed,  except  in  small  engines  up  to  10 
horse-power,  and  is  applicable  only  to  engines  in  which 


FIG.  33. — Inertia  governor. 

the  "  hit  and  miss  "  system  is  employed  (Fig.  33) .  The 
second  form  is  more  widely  used,  and  is  applicable  to 
engines  having  "  hit-and-miss  "  or  variable  admission 
devices.  In  the  first  form,  the  governor  simply  displaces 
a  very  light  member,  whatever  may  be  the  size  of  the 
engine,  for  which  reason  the  dimensions  are  very  small. 
In  the  second  form,  on  the  other  hand,  the  governor 
acts  either  on  a  conical  sleeve  or  on  some  other  regulat- 
ing member  offering  resistance.  Evidently,  in  order  to 


GOVERNORS 


53 


overcome  the  reactions  to  which  it  is  subjected,  it  must 
be  as  heavy  and  powerful  as  a  steam-engine  governor. 
Sufficient  allowance  is  made  in  a  good  engine  for 
variation  in  the  number  of  revolutions  between  no  load 
and  full  load,  not  greater  than  two  per  cent,  if  the 
admission  be  of  the  "  hit-and-miss  "  type,  and  five  per 
cent,  if  it  be  of  the  variable  type. 

2.  Cyclic  Regularity. — This  term  means  simply  that 
the  speed  of  the  engine  is  constant  in  a  single  revolu- 
tion. In  practice  this  is  never  attained.  Allowance  is 
made  in  engines  used  for  driving  direct-current  dyna- 
mos for  a  variation  of  about  -^-;  while  in  industrial 
engines  a  variation  of  -^  is  permissible.  Cyclic  varia- 
tion depends  only  on  the  weight  of  the  fly-wheel ; 
whereas  variation  in  the  number  of  revolutions  is  deter- 
mined chiefly  by  the  governor. 

Governors. — Diagrams  are  here  presented  of  the 
principal  types  of  governors — the  inertia  governor,  the 
ball  or  centrifugal  governor  controlling  an  admission- 
valve  of  the  "  hit-and-miss  "  type  (Fig.  34),  and  the 
ball  or  centrifugal  governor  controlling  a  variable  gas- 
admission  valve  (Fig.  35). 

In  distinguishing  between  the  operation  of  the  two 
last-mentioned  types,  it  may  be  stated  that  the  former 
bears  the  same  relation  to  the  hit-and-miss  gear  as  it 
does,  for  example,  to  the  valve  gear  of  a  Corliss  steam- 
engine.  In  other  words,  it  is  an  apparatus  that  indi- 
cates without  inducing,  admission  or  cut-off.  The  sec- 
ond type,  on  the  other  hand,  operates  by  means  of  slides 
and  the  like,  as  in  the  Ridder  type  of  engine,  in  which 


54      GAS-ENGINES    AND    PRODUCERS 

it  controls  the  displacement  of  the  cut-off  or  distribu- 
tion slide-valve  and  is  subjected  to  variable  forces,  de- 
pending on  the  pressure,  lubrication,  the  condition  of 
the  stuffing-boxes,  and  the  like. 

In  gas  as  well  as  in  steam  engines,  designs  are  to  be 
commended  which  shield  the  delicate  mechanism  from 
strains  and  stresses  that  are  likely  to  destroy  its  sensi- 


FIG.  34. — "Hit-and-miss"  governor. 

tiveness,  as  is  the  case  in  the  automatic  cut-off  of  the 
Corliss  steam-engine. 

Governors  should  be  provided  with  means  to  permit 
the  manual  variation  of  the  speed  while  the  engine  is  in 
operation. 

For  small  motors,  one  of  the  most  widely  used  ad- 
mission devices  is  that  of  the  "  hit-and-miss  "  type.  As 
its  name  indicates,  this  admission  arrangement  allows 


GOVERNORS  55 

r. 

a  given  quantity  of  gas  to  enter  the  cylinder  for  a  num- 
ber of  consecutive  intervals,  until  the  engine  is  about 
to  exceed  its  normal  speed.  Thereupon  the  governor 
cuts  off  the  gas  entirely.  The  result  is  that,  in  this 
system,  the  number  of  admissions  is  variable,  but  that 
each  admitted  charge  is  composed  of  a  constant  pro- 
portion of  gas  and  air. 

The  governors  employed  for  the  "  hit-and-miss " 
type  are  either  "  inertia  "  or  "  centrifugal  "  governors. 

Inertia  governors  (Fig.  33)  are  less  sensitive  than 
those  of  the  centrifugal  type.  They  are  generally  ap- 
plied only  to  industrial  engines  of  small  power,  in 
which  regularity  of  operation  is  a  secondary  considera- 
tion. 

Centrifugal  governors  employed  for  gas-engines 
with  "  hit-and-miss  "  regulation  are,  as  a  general  rule, 
noteworthy  for  their  small  size,  which  is  accounted  for 
by  'the  fact  that,  in  most  systems,  merely  a  movable 
member  is  placed  between  the  admission-controlling 
means  and  the  valve-stem  (Fig.  34).  It  follows  that 
this  method  of  operation  relieves  the  governor  of  the 
necessity  of  overcoming  the  resistance  of  the  weight  of 
moving  parts,  more  or  less  effectually  lubricated,  and 
subjected  to  the  reaction  of  the  parts  which  they  con- 
trol. 

In  engines  equipped  with  variable  admission  devices 
for  the  gas  or  the  explosive  mixture,  the  governor  act- 
uates a  sleeve  on  which  the  admission-cam  is  fastened 
(Fig.  35).  Or,  the  governor  may  displace  a  conical 
cam,  the  reaction  of  which,  on  contact  with  the  lever, 


56      GAS-ENGINES    AND    PRODUCERS 

destroys  the  stability  of  the  governor.  These  condi- 
tions justify  the  employment  of  powerful  governors 
which,  on  account  of  the  inertia  of  their  parts,  diminish 
the  reactionary  forces  encountered. 

The  centrifugal  governor  should  be  sufficiently  ef- 
fectual to  prevent  variations  in  the  number  of  revolu- 
tions within  the  limits  of  2  to  3  per  cent,  between  no 
load  and  approximately  full  load.  Under  equivalent 


FIG.  35. — Variable  admission  governor. 

conditions,  the  inertia  governor  can  hardly  be  relied 
upon  for  a  coefficient  of  regularity  greater  than  4  to 
5  per  cent. 

The  manner  of  a  governor's  operation  is  necessarily 
dependent  on  the  admission  system  adopted.  And  the 
admission  system  varies  essentially  with  the  size,  the 
purpose  of  the  engine,  and  the  character  of  the  fuel  em- 
ployed. 

Vertical  Engines. — For  some  years  past  there  seems 
to  have  been  a  tendency  in  Europe  to  use  horizontal 
instead  of  vertical  engines,  especially  since  engines  of 


VERTICAL   ENGINES 


57 


more  than  10  or  15  horse-power  have  been  extensively 
used  for  industrial  purposes.  The  vertical  type  is  used 
for  i  to  8  horse-power  engines,  with  the  cylinder  in  the 
lower  part  of  the  frame,  and  the  shaft  and  its  fly-wheel 
in  the  upper  part  (Fig.  36).  The  only  merit  to  be 
attributed  to  this  arrangement  is  a  great  saving  of  space. 
It  is  evident,  however,  that  beyond  a  certain  size  and 
power,  such  engines  are  unstable.  In  America  particu- 


FIG.  36. — Vertical  engine. 

larly,  many  manufacturers  of  high-power  engines  (50 
to  100  horse-power  or  more)  prefer  the  vertical  or 
"  steam-hammer  "  arrangement,  which  consists  in  plac- 
ing the  cylinder  in  the  upper  part,  and  the  shaft  in  the 
lower  part  of  the  frame  as  close  to  the  ground  as  possi- 
ble (Figs.  37  and  38).  The  problem  of  saving  space,  as 
well  as  that  of  insuring  stability,  is  thus  solved,  so  that 
it  is  easily  possible  to  run  up  the  speed  of  the  engine. 
There  is  also  the  advantage  that  the  shaft  of  a  dynamo 


58      GAS-ENGINES    AND    PRODUCERS 


FIG.  37. — Section  through  an  engine  of  the  vertical  or  "steam -hammer"  type. 


MERITS  OF  VERTICAL   ENGINES 


59 


can  be  directly  coupled  up  with  the  crank-shaft  of  the 
engine,  thus  dispensing  with  a  belt,  which,  at  the  least, 


0> 

•a 


absorbs  4  to  6  per  cent,  of  the  total  power.    It  should, 
nevertheless,  be  borne  in  mind  that  the  direct  coupling 


60      GAS-ENGINES    AND    PRODUCERS 

of  electric  generators  to  engine-shafts  implies  the  use 
of  extremely  large  and,  therefore,  of  extremely  costly 
dynamos.  Furthermore,  by  reason  of  this  arrangement, 
groups  of  electro-generators  can  be  disposed  in  a  com- 
paratively small  amount  of  space.  Some  English  man- 
ufacturers are  also  beginning  to  adopt  the  "  steam- 
hammer  "  type  of  engine  for  high  powers,  the  result 
being  a  marked  saving  in  material  and  lowering  of  the 
cost  of  installation. 

Power  of  the  Engine.— The  first  thing  to  be  con- 
sidered is  that  the  power  of  a  gas-engine  is  always  given 
in  "  effective  "  horse-power,  and  that  the  power  of  a. 
steam-engine  is  always  given  in  "  indicated  "  horse- 
power in  contracts  of  sale.  In  England  and  in  the 
United  States,  the  expression  "  nominal  "  horse-power 
is  still  employed.  It  may  be  advisable  to  define  these 
various  terms  exactly,  since  unscrupulous  dealers,  to 
the  buyer's  loss,  have  done  much  to  confuse  them. 

"  Indicated  "  horse-power  is  a  designation  applied  to 
the  theoretical  power  produced  by  the  action  of  the 
motive  agent  on  the  piston.  The  work  performed  is 
measured  on  an  indicator  card,  by  means  of  which  the 
average  pressure  to  be  considered  in  the  computation  of 
the  theoretical  power  is  ascertained. 

The  "  effective  "  or  brake  horse-power  is  equal  to  the 
"  indicated  "  horse-power,  less  the  energy  absorbed  by 
passive  resistance,  friction  of  the  moving  parts,  etc. 

The  "  effective  "  work  is  an  experimental  term  ap- 
plied to  the  power  actually  developed  at  the  shaft 
This  work  is  of  interest  solely  to  the  engine  user. 


DEFINITIONS    OF   "  POWER"  61 

i  9 

In  a  well-built  motor,  in  which  the  passive  resistance 
by  reason  of  the  correct  adjustment  and  simplicity  of 
the  parts,  is  reduced  to  a  minimum,  the  "  effective  " 
horse-power  is  about  80  to  87  per  cent,  of  the  u  indi- 
cated "  horse-power,  when  the  engine  runs  under  full 
load.  This  reduced  output  is  usually  called  the 
"  mechanical  efficiency  "  of  the  engine. 

"  Nominal  "  horse-power  is  an  arbitrary  term  in  the 
sense  in  which  it  is  used  in  England  and  America, 
where  it  is  quite  common.  The  manufacturers  them- 
selves do  not  seem  to  agree  on  its  absolute  value.  A 
"  nominal  "  horse-power,  however,  is  equal  to  anything 
from  3  to  4  "  effective  "  horse-power.  The  uncertainty 
which  ensues  from  the  use  of  the  term  should  lead  to 
its  abandonment. 

In  installing  a  motor,  the  determination  of  its  horse- 
power is  a  matter  of  grave  importance,  which  should 
not  be  considered  as  if  the  motor  were  a  steam-engine 
or  an  engine  of  some  other  type.  It  must  not  be  for- 
gotten that,  especially  at  full  load,  explosion-engines 
are  most  efficient,  and  that,  under  these  conditions,  it 
will  generally  be  advisable  to  subordinate  the  utility  of 
having  a  reserve  power  to  the  economy  which  follows 
from  the  employment  of  a  motor  running  at  a  load 
close  to  its  maximum  capacity.  On  the  other  hand,  the 
gas-engine  user  is  unwilling  to  believe  that  the  stipu- 
lated horse-power  of  the  motor  which  is  sold  -to  him  is 
the  greatest  that  it  is  capable  of  developing  under  in- 
dustrial conditions.  Business  competition  has  led  some 
firms  to  sell  their  engines  to  meet  these  conditions.  It 


62      GAS-ENGINES    AND    PRODUCERS 

is  probably  not  stretching  the  truth  too  far  to  declare 
that  80  per  cent,  of  the  engines  sold  with  no  exact  con- 
tract specifications  are  incapable  of  maintaining  fo-r 
more  than  a  half  hour  the  power  which  is  attributed 
to  them,  and  which  the  buyer  expects.  It  follows  that 
.the  power  at  which  the  engine  is  sold  should  be  both 
industrially  realized  and  maintained,  if  need  be,  for  an 
entire  day,  without  the  engine's  showing  the  slightest 

perturbation,  or  faltering  in  its  silent  and  regular  opera- 

• 

tion.  To  attain  this  end,  it  is  essential  that  the  energy 
developed  by  the  engine  in  normal  or  constant  opera- 
tion should  not  exceed  90  to  95  per  cent,  of  the  maxi- 
mum power  which  it  is  able  to  yield,  and  which  may  be 
termed  its  u  utmost  power."  As  a  general  rule, 
especially  for  installations  in  which  the  power  fluctu- 
ates from  the  lowest  possible  to  double  this,  as  much 
attention  must  be  paid  to  the  consumption  at  half  load 
as  at  full  load;  and  preference  should  be  given  to  the 
engine  which,  other  things  being  equal,  will  operate 
most  economically  at  its  lowest  load.  In  this  case  the 
consumption  per  effective  horse-power  is  appreciably 
higher.  Generally,  this  consumption  is  greater  by  20 
to  30  per  cent,  than  that  at  full  load.  This  is  partic- 
ularly true  of  the  single-acting  engines  so  widely  used 
for  horse-powers  less  than  100  to  150. 

In  some  double  or  triple-acting  engines,  according 
to  certain  writers,  the  diminution  in  the  consumption 
will  hardly  be  proportional  to  the  diminution  of  the 
power,  or  at  any  rate,  the  difference  between  the  con- 
sumption per  B.  H.  P.  at  full  load  and  at  reduced  load 


ENGINE   POWER  63 

• 

will  be  less  than  in  other  engines.  It  should  be  ob- 
served, however,  that  this  statement  is  apparently  not 
borne  out  by  experiments  which  the  author  has  had 
occasion  to  make.  To  a  slight  degree,  this  economy  is 
obtained  at  the  cost  of  simplicity,  and  consequently,  at 
the  cost  of  the  engine.  At  all  events,  the  engines  have 
the  merit  of  great  cyclic  regularity,  rendering  them 
serviceable  for  driving  electric-light  dynamos;  but  this 
regularity  can  also  be  attained  by  the  use  of  the  extra 
heavy  fly-wheels  which  English  firms,  in  particular, 
have  introduced. 

Automatic  Starting.— When  the  gas-engine  was  first 
introduced,  starting  was  effected  simply  by  manually 
turning  the  fly-wheel  until  steady  running  was  assured. 
This  procedure,  altogether  too  crude  in  its  way,  is 
attended  with  some  danger.  In  a  few  countries  it  is 
prohibited  by  laws  regulating  the  employment  of  in- 
dustrial machinery.  If  the  engine  be  of  rather  large 
size — one,  moreover,  which  operates  at  high  pres- 
sure— such  a  method  of  starting  is  very  troublesome. 
For  these  reasons,  among  others,  manufacturers  have 
devised  automatic  means  of  setting  a  gas-engine  in 
motion. 

Of  such  automatic  devices,  the  first  that  shall  be 
mentioned  is  a  combination  of  pipes,  provided  with 
cocks,  by  the  manipulation  of  which,  a  certain  amount 
of  gas,  drawn  from  the  supply  pipe,  is  introduced  into 
the  engine-cylinder.  The  piston  is  first  placed  in  a 
suitable  position,  and  behind  it  a  mixture  is  formed 
which  is  ignited  by  a  naked  flame  situated  near  a  con- 


64      GAS-ENGINES    AND    PRODUCERS 

venient  orifice.  When  the  explosion  takes  place  the 
ignition-orifice  is  automatically  closed,  and  the  .piston 
is  given  its  motive  impulse.  The  engine  thus  started 
continues  to  run  in  accordance  with  the  regular  recur- 
rence of  the  cycles.  In  this  system,  starting  is  effected 
by  the  explosion  of  a  mixture,  without  previous  com- 
pression. 

Some  designers  have  devised  a  system  of  hand- 
pumps  which  compress  in  the  cylinder  a  mixture  of 
air  and  gas,  ignited  at  the  proper  time  by  allowing  it 
to  come  into  contact  with  the  igniter,  through  the  man- 
ipulation of  cocks  (Fig.  39). 

These  two  methods  are  not  absolutely  effective. 
They  require  a  certain  deftness  which  can  be  acquired 
only  after  some  practice.  Furthermore,  they  are  ob- 
jectionable because  the  starting  is  effected  too  violently, 
and  because  the  instantaneous  explosion  subjects  the 
stationary  piston,  crank,  and  fly-wheel  to  a  shock  so 
sudden  that  they  may  be  severely  strained  and  may  even 
break.  Moreover,  the  slightest  leakage  in  one  of  the 
valves  or  checks  may  cause  the  entire  system  to  fail, 
and,  particularly  in  the  case  of  the  pump,  may  induce 
a  back  explosion  exceedingly  dangerous  to  the  man  in 
charge  of  the  engine. 

These  systems  are  now  almost  generally  supplanted 
by  the  compressed-air  system,  which  is  simpler,  less 
dangerous,  and  more  certain  in  its  effect. 

The  elements  comprising  the  system  in  question  in- 
clude essentially  a  reservoir  of  thick  sheet  iron,  capable 
of  resisting  a  pressure  of  180  to  225  pounds  and  suffi- 


AUTOMATIC   STARTER  65 

t      . 

cient  in  capacity  to  start  an  engine  several  times.  This 
reservoir  is  connected  with  the  engine  by  piping,  which 
is  disposed  in  one  of  two  ways,  depending  upon  whether 


FIG.  39. — Tangye  starter. 

the  reservoir  is  charged  by  the  engine  itself  operatively 
connected  with  the  compressor,  or  by  an  independent 
compressor,  mechanically  operated. 

In  the  first  case,  the  pipe  is  provided  with  a  stop- 
cock, mounted  adjacent  to  the  cylinder,  and  with  a 
check-valve.  When  the  engine  is  started  and  the  gas 


66      GAS-ENGINES    AND    PRODUCERS 

cut  off,  the  air  is  drawn  in  at  each  cycle  and  driven 
back  into  the  reservoir  during  the  period  of  compres- 
sion. When  the  engine,  running  under  these  conditions 
by  reason  of  the  inertia  of  the  fly-wheel,  begins  to  slow 
down,  the  check-valve  is  closed  and  the  gas-admission 
valve  opened,  so  as  to  produce  several  explosions  and  to 
impart  a  certain  speed  to  the  engine  in  order  to  con- 
tinue the  charging  of  the  reservoir  with  compressed  air. 
This  done,  the  valve  on  the  reservoir  itself  is  tightly 
closed,  as  well  as  the  check-valve,  so  as  to  avoid  any 
leakage  likely  to  cause  a  fall  in  the  reservoir's  pressure. 
In  the  second  case,  which  applies  particularly  to 
engines  of  more  than  50  horse-power,  the  charging  pipe 
connected  with  the  reservoir  is  necessarily  independent 
of  the  pipe  by  means  of  which  the  motor  is  started. 
The  reservoir  having  been  filled  and  the  decompres- 
sion cam  thrown  into  gear,  starting  is  accomplished  : 

1.  By  placing  the  piston  in  starting  position,  which 
corresponds  with  a  crank  inclination  of  10  to  20  degrees 
in  the  direction  of  the  piston's  movement,  from  the 
rear  dead  center,  immediately  after  the  period  of  com- 
pression; 

2.  By  opening  the  reservoir-valve; 

3.  By    allowing   the    compressed    air    to.  enter   the 
cylinder  rapidly,  through  the  quick  manipulation  of 
the  stop-cock,  which  is  closed  again  when  the  impulse 
is  given  and  reopened  at  the  corresponding  period  of 
the  following  cycle,  this  operation  being  repeated  sev- 
eral times  in  order  to  impart  sufficient  speed  to  the 
motor; 


AUTOMATIC   STARTERS  67 

p 
4.  By  opening  the  gas-valve  and  finally  closing  the 

two  valves  of  the  compressed-air  pipe. 

The  pipes  and  compressed-air  reservoirs  should  be 
perfectly  tight.  The  reservoirs  should  have  a  capacity 
in  inverse  ratio  to  the  pressure  under  which  they  are 
placed,  i.e.,  they  increase  in  size  as  the  pressure  de- 
creases. If,  for  example,  the  reservoirs  should  be  op- 
erated normally  at  a  pressure  of  105  to  120  pounds  per 
square  inch,  their  capacity  should  be  at  least  five  or  six 
times  the  volume  of  the  engine-cylinder.  If  these  res- 
ervoirs are  charged  by  the  engine  itself,  the  pressure 
will  always  be  less  by  15  to  20  per  cent,  than  that 
of  the  compression. 


CHAPTER  III 

THE   INSTALLATION  OF  AN   ENGINE 

IN  the  preceding  chapter  the  various  structural  de- 
tails of  an  engine  have  been  summarized  and  those  ar- 
rangements indicated  which,  from  a  general  stand- 
point, seem  most  commendable.  No  particular  system 
has  been  described  in  order  that  this  manual  might  be 
kept  within  proper  limits.  Moreover,  the  best-knowTn 
writers,  such  as  Hutton,  Hiscox,  Parsell  and  Weed,  in 
America;  Aime  Witz,  in  France;  Dugald  Clerk,  Fred- 
erick Grover,  and  the  late  Bryan  Donkin,  in  England; 
Giildner,  Schottler,  Thering,  in  Germany,  have  pub- 
lished very  full  descriptive  works  on  the  various  types 
of  engines. 

We  shall  now  consider  the  various  methods  which 
seem  preferable  in  installing  an  engine.  The  directions 
to  be  given,  the  author  believes,  have  not  been  hitherto 
published  in  any  work,  and  are  here  formulated,  after 
an  experience  of  fifteen  years,  acquired  in  testing  over 
400  engines  of  all  kinds,  and  in  studying  the  methods 
of  the  'leading  gas-engine-building  firms  in  the  chief 
industrial  centers  of  Europe  and  America. 

Location. — The  engine  should  be  preferably  located 
in  a  well-lighted  place,  accessible  for  inspection  and 
maintenance,  and  should  be  kept  entirely  free  from 

68 


GAS-PIPES  60 

t  y 

dust.  As  a  general  rule,  the  engine  space  should  be  en- 
closed. An  engine  should  not  be  located  in  a  cellar,  on 
a  damp  floor,  or  in  badly  illuminated  and  ventilated 
places. 

Gas-Pipes. — The  pipes  by  which  fuel  is  conducted 
to  engines,  driven  by  street-gas,  and  the  gas-bags,  etc., 
are  rarely  altogether  free  from  leakage.  For  this 
reason,  the  engine-room  should  be  as  well  ventilated  as 
possible  in  the  interest  of  safety.  Long  lines  of  pipe 
between  the  meter  and  the  engine  should  be  avoided, 
for  the  sake  of  economy,  since  the  chances  for  leakage 
increase  with  the  length  of  the  pipe.  It  seldom  happens 
that  the  leakage  of  a  pipe  30  to  50  feet  long,  supplying 
a  30  horse-power  engine,  is  much  less  than  90  cubic  feet 
per  hour.  The  beneficial  effect  of  short  supply  pipes 
between  meter  and  engine  on  the  running  of  the  engine 
is  another  point  to  be  kept  in  mind. 

An  engine  should  be  supplied  with  gas  as  cool  as 
possible,  which  condition  is  seldom  realized  if  long 
pipe  lines  be  employed,  extending  through  workshops, 
the  temperature  of  which  is  usually  higher  than  that  of 
underground  piping.  On  the  other  hand,  pipes  should 
not  be  exposed  to  the  freezing  temperature  of  winter, 
since  the  frost  formed  within  the  pipe,  and  particularly 
the  crystalline  deposition  of  naphthaline,  reduces,  the 
cross  section  and  sometimes  clogs  the  passage.  Often 
it  happens  that  water  condenses  in  the  pipes;  conse- 
quently, the  piping  should  be  disposed  so  as  to  obviate 
inclines,  in  which  the  water  can  collect  in  pockets.  An 
accumulation  of  water  is  usually  manifested  by  fluctua- 


7° 


GAS-ENGINES    AND    PRODUCERS 


tions  in  the  flame  of  the  burner.  In  places  where  water 
can  collect,  a  drain-cock  should  be  inserted.  In  places 
exposed  to  frost,  a  cock  or  a  plug  should  be  provided, 
so  that  a  liquid  can  be  introduced  to  dissolve  the  naph- 
thaline. To  insure  the  perfect  operation  of  the  engine, 
as  well  as  to  avoid  fluctuations  in  nearby  lights,  pipes 
having  a  large  diameter  should  preferably  be  em- 
ployed. The  cross-section  should  not  be  less  than  that 
of  the  discharge-pipe  of  the  meter,  selected  in  accord- 
ance with  the  prescriptions  of  the  following  table: 

GAS-METERS. 


Capacity. 

Normal 
hourly  flow. 

Dimension  in  inches. 

Diameter 
of  pipe 
in  inches. 

Power  of  en- 
gine to  be  fed. 

Height. 

Width. 

Depth. 

3    burners 

I4.726cu.ft. 

13 

II 

9H 

0.590 

i/a    h.-p. 

s    ;; 

24.710    " 

18 

i3t 

I0t 

0.787 

3/4      " 

10          " 

49.420    <( 

21* 

18* 

"A 

0.984 

1-2        " 

20          " 

98.840    " 

*3A 

I9H 

'5  A 

1.181 

3-4     " 

30          " 

148.260    " 

25i 

2Mi 

'8T\ 

1.456 

5-6     " 

So       " 

247.100    " 

29! 

24TV 

20T75 

1.592 

7-10     <{ 

60       " 

296.520    tl 

3°A 

251 

251 

1.671 

11-14 

80       " 

395-360    l> 

33T5ir 

30A 

27i 

1.968 

iS-9     " 

100          " 

494.2OO     ' 

35 

33TTT 

29H 

1.968 

20-25     " 

150    " 

741.300    " 

4°A 

4°& 

33iJ 

— 

30-40 

The  records  made  are  exact  only  when  the  meters 
(Fig.  40)  are  installed  and  operated  under  normal  con- 
ditions. Two  chief  causes  tend  to  falsify  the  measure- 
ments in  wet  meters :  ( i )  evaporation  of  the  water,  (2) 
the  failure  to  have  the  meter  level. 

Evaporation  occurs  incessantly,,  owing  to  the  flow- 
Ing  of  the  gas  through  the  apparatus,  and  increases  with 
a  rise  in  the  temperature  of  the  atmosphere  surrounding 
the  meter.  Consequently  this  temperature  must  be  kept 


METERS 


71 


down,  for  which  reason  the  meter  should  be  placed  as 
near  the  ground  as  possible.  The  evaporation  also  in- 
creases with  the  volume  of  gas  delivered.  Hence  the 
meter  should  not  supply  more  than  the  volume  for 
which  it  was  intended.  In  order  to  facilitate  the  re- 
turn of  the  water  of  condensation  to  the  meter  and  to 
prevent  its  accumulation,  the  pipes  should  be  inclined 
as  far  as  possible  toward  the  meter.  The  lowering  of 


FIG.  40. — Wet  gas-meter. 

the  water-level  in  the  meter  benefits  the  consumer  at 
the  expense  of  the  gas  company. 

Inclination  from  the  horizontal  has  an  effect  that 
varies  with  the  direction  of  inclination.  If  the  meter 
be  inclined  forward,  or  from  left  to  right,  the  water 
can  flow  out  by  the  lateral  opening  at  the  level,  and  in- 
correct measurements  are  made  to  the  consumer's  cost. 

During  winter,  the  meter  should  be  protected  from 
cold.  The  simplest  way  to  accomplish  this,  is  to  wrap 
substances  around  the  meter  which  are  poor  conductors 
of  heat,  such  as  straw,  hay,  rags,  cotton,  and  the  like. 
Freezing  of  the  water  can  also  be  prevented  by  the  addi- 


72      GAS-ENGINES    AND    PRODUCERS 

tion  of  alcohol  in  the  proportion  of  2  pints  per  burner. 
The  water  is  thus  enabled  to  withstand  a  temperature 
of  about  5  degrees  F.  below  zero.  Instead  of  alcohol, 
glycerine  in  the  same  proportions  can  be  employed, 
care  being  taken  that  the  glycerine  is  neutral,  in  order 


FIG.  41. — Dry  gas-meter. 

that  the  meter  may  not  be  attacked  by  the  acids  which 
the  liquid  sometimes  contains. 

Dry  Meters. — Dry  meters  are  employed  chiefly  in 
cold  climates,  where  wet  meters  could  be  protected  only 
with  difficulty  and  where  the  water  is  likely  to  freeze. 
In  the  United  States  the  dry  meter  is  the  type  most 
widely  employed.  In  Sweden  and  in  Holland  it  is  also 
generally  introduced  (Fig.  41). 

In  the  matter  of  accuracy  of  measurement  there  is 
little,  if  any,  difference  between  wet  and  dry  meters. 
The  dry  meter  has  the  merit  of  measuring  correctly  re- 


DRY    METERS 


73 


gardless  of  the  fluctuations  in  the  water  level.  On  the 
other  hand,  it  is  open  to  the  objection  of  absorbing 
somewhat  more  pressure  than  the  wet  meter,  after  hav- 
ing been  in  operation  for  a  certain  length  of  time. 


FIG.  42. — Section  through  a  dry  gas-meter. 

This  is  an  objection  of  no  great  weight;  for  there  is 
always  enough  pressure  in  the  mains  and  pipes  to 
operate  a  meter. 

In  many  cases,  where  the  employment  of  non-freez- 
ing liquids  is  necessary,  the  dry  meter  may  be  used  to 


74      GAS-ENGINES    AND    PRODUCERS 

advantage,  since  all  such  liquids  have  more  or  less  cor- 
roding effect  on  sheet  lead  and  even  tin,  depending 
upon  the  composition  of  the  gas. 

The  dry  meter  comprises  two  bellows,  operating  in 
a  casing  divided  into  two  compartments  by  a  central 


FIG.  43.— Section  through  a  dry  gas-meter. 

partition.  The  gas  is  distributed  on  one  or  the  other 
side  of  the  bellows,  by  slides  B.  The  slides  B  are  pro- 
vided with  cranks  £,  controlled  by  levers  M,  act- 
uated by  transmission  shafts  O,  driven  by  the  bellows. 
The  meter  is  adjusted  by  a  screw  which  changes  the 
throw  of  the  cranks  E  and  consequently  affects  the  bel- 


CONSTRUCTION  OF  A  DRY  METER 


75 


lows.  The  movement  of  the  crank-shaft  D  is  trans- 
mitted to  the  indicating  apparatus.  In  order  to  obvi- 
ate any  leakage,  this  shaft  passes  through  a  stuffing-box, 


FIG.  44. — Rubber  bag  to  prevent  fluctuations  of  the  ignition  flame. 

G.  The  diagrams  (Figs.  42-43)  show  the  construction 
of  a  dry  meter,  the  arrows  indicating  the  course  taken 
by  the  gas. 

Care  should  be  taken  to  provide  the  gas-pipe  with 
a  drain-cock,  at  a  point  near  the  engine.  By  means  of 
this  cock,  any  air  in  the  pipe  can  be  allowed  to 


76      GAS-ENGINES    AND    PRODUCERS 


FIG.  45. — Rubber  bags  on  gas-pipes. 


PRESSURE-REGULATORS  77 


• 


escape  before  starting;  otherwise  the  engine  can  be  set 
in  motion  only  with  difficulty.  If  the  engine  be  pro- 
vided with  an  incandescent  tube,  the  gas-supply  pipe  of 
the  igniter  should  be  fitted  with  a  small  rubber  pouch 
or  bag,  in  order  to  obviate  fluctuations  in  the  burner 
flame,  caused  by  variations  in  the  pressure  (Fig.  44). 
As  a  general  rule,  the  supply-pipe  should  be  connected 
with  the  main  pipe  on  the  forward  side  of  the  bags  and 
gas-governors.  The  main  pipe  and  all  other  piping 
near  the  engine  should  extend  underground,  so  that 
free  access  to  the  motor  from  all  sides  can  be  obtained, 
without  possibility  of  injury. 

Anti-pulsators ,  Bags ,  Pressure-Regulators .  — The 
most  commonly  employed  means  of  preventing  fluctua- 
tion of  nearby  lights,  due  to  the  sharp  strokes  of  the  en- 
gine, consists  in  providing  the  gas-supply  pipe  with  rub- 
ber bags  (Fig.  45),  which  form  reservoirs  for  the  gas 
and,  by  reason  of  their  elasticity,  counteract  the  effect 
produced  by  the  suction  of  the  engine.  Nevertheless,  in 
order  to  insure  a  supply  of  gas  at  a  constant  pressure, 
which  is  necessary  for  the  perfect  operation  of  the  en- 
gine, there  are  generally  used,  in  addition  to  the  bags, 
devices  called  gas-governors,  or  anti-pulsators  (Fig. 

46). 

Although  these  devices  are  constructed  in  different 
ways,  the  underlying  principle  is  the  same  in  all.  They 
comprise  a  metallic  casing,  containing  a  flexible  dia- 
phragm of  rubber  or  of  some  fabric  impermeable  to 
gas.  Suction  of  the  engine  creates  a  vacuum  in  the  cas- 
ing. The  diaphragm  bends,  thereby  actuating  a  valve, 


78      GAS-ENGINES    AND    PRODUCERS 

which  cuts  off  the  gas  supply.     During  the  three  fol- 
lowing periods  (compression,  explosion,  and  exhaust) 
the  gas,  by  reason  of  its  pressure  on  the  diaphragm, 
opens  the  valve  and  fills  the  casing,  ready  for  the  next 
suction  stroke. 

Other  devices,  which  are  never  sold  with  the  engine, 
but  are  rendered  necessary  by  reason  of  the  conditions 
imposed  by  the  gas  supply  are  sold  under  the  name 


FIG.  46. — An  anti-pulsator. 

"  pressure-regulators  "  (Fig.  47).  They  consist  of  a 
bell,  floating  in  a  reservoir  containing  water  and  gly- 
cerine (or  mercury),  and  likewise  actuate  a  valve 
which  partially  controls  the  flow  of  gas.  This  valve 
being  balanced,  its  mechanical  action  is  the  more  cer- 
tain. Such  devices  are  very  effective  in  maintaining 
the  steadiness  of  lights.  On  the  other  hand,  they  are 
often  an  obstacle  to  the  operation  of  the  engine  be- 
cause they  reduce  the  flow  and  pressure  of  the  gas  too 
much.  In  order  to  obviate  this  difficulty,  a  pressure- 
regulator  should  be  chosen  with  discrimination,  and  of 


or 


PRESSURE-REGULATORS 


of 


sufficiently  large  size  to  insure  the  maintenance  of  an 
adequate  supply  of  gas  to  the  engine.  Frequent  ex- 
aminations should  be  made  to  ascertain  if  the  bell  of 
the  regulator  is  immersed  in  the  liquid.  In  the  case  of 
anti-pulsators,  care  should  be  taken  that  they  are  not 
spattered  with  oil,  which  has  a  disastrous  effect  on  rub- 
ber. Anti-pulsators  are  generally  mounted  about  4 


FIG.  47. — A  pressure-regulator. 

inches  from  a  wall,  in  order  that  the  diaphragm  may 
be  actuated  by  hand,  if  need  be. 

Precautions. — In  order  not  to  strain  the  rubber  of 
the  bags  or  of  the  anti-pulsators,  it  is  advisable  to  place 
a  stop-cock  in  advance  of  these  devices  so  that  they  can 
not  be  filled  while  the  motor  is  at  rest. 

The  capacity  of  the  rubber  bags  that  can  be  bought 


8o      GAS-ENGINES    AND    PRODUCERS 

in  the  market  being  limited,  it  is  necessary  to  place  one, 
two,  or  three  extra  bags  in  series  (Figs.  48  and  49),  for 
large  pipes;  but  it  should  be  borne  in  mind  that  the 


FIGS.  48-49. — Arrangement  of  rubber  bags. 

total  section  of  the  branch  pipes  should  be  at  least  equal 
to  that  of  the  main  pipe.  It  is  also  advisable  to  extend 
the  tube  completely  through  the  bag  as  shown  in  Figs. 
48  and  49. 

If  there  be  two  branch  pipes  the  minimum  diameter 


DIAMETER  OF   PIPES 


81 


which  meets  this  requirement  is  ascertained  as  follows: 
Draw  to  any  scale  a  semicircle  having  a  diameter 
equal  or  proportional  to  that  of  the  main  pipe  (Fig. 
50) .  The  sides  of  the  isosceles  triangle  inscribed  with- 
in this  semicircle  give  the  minimum  diameter  of  each 
of  the  branch  pipes. 

Sometimes  engines  are  provided  with  a  cock  having 
an  arrangement  by  means  of  which  the  gas  feed  is  per- 
manently regulated,  according  to  the  quality  and  pres- 


FIG.  51, 


sure  of  the  gas  and  according  to  the  load  at  which  the 
engine  is  to  run.  This  renders  it  possible  to  open  the 
cock  always  to  the  same  point  (Fig.  51). 

Air  Suction. — In  a  special  chapter  the  precautions  to 
be  taken  to  counteract  the  influence  of  the  suction  of  the 
engine  in  causing  vibration  will  be  treated.  The  man- 
ner in  which  the  suction  of  air  is  effected  necessarily 
has  as  marked  an  influence  on  the  operation  of  the  en- 
gine as  the  supply  of  gas,  since  air  and  gas  constitute 
the  explosive  mixture. 

Resistance  to  the  suction  of  air  should  be  carefully 


82      GAS-ENGINES    AND    PRODUCERS 

avoided,  for  which  reason  the  length  of  the  pipe  should 
be  reduced  to  a  minimum,  and  its  cross-section  kept  at 
least  equal  to  that  of  the  air  inlet  of  the  engine.  Since 
the  quality  of  street-gas  varies  with  each  city,  the 
proper  proportions  of  gas  and  air  are  not  constant.  In 
order  that  these  proportions  may  be  regulated,  it  is  a 
matter  of  some  importance  to  fit  some  suitable  device 
on  the  pipe.  Good  engines  are  provided  with  a  plug 
or  flap  valve.  Generally  the  air-pipe  terminates  either 
in  the  hollowed  portion  of  the  frame,  or  in  an  inde- 
pendent pot,  or  air  chest.  The  first  arrangement  is  not 
to  be  recommended  for  engines  over  20  to  25  horse- 
power. Accidents  may  result,  such  as  the  breaking  of 
the  frame  by  reason  of  back  firing,  of  which  more  will 
be  said  later.  If  an  independent  chest  be  employed,  its 
closeness  to  the  ground  renders  it  possible  for  dust 
easily  to  pass  through  the  air-holes  in  the  walls  at  the 
moment  of  suction,  and  even  to  enter  the  cylinder, 
where  its  presence  is  particularly  harmful,  leading,  as 
it  does,  to  the  rapid  wear  of  the  rubbing  surfaces.  This 
evil  can  be  largely  remedied  by  filling  the  air-chest 
with  cocoa  fiber  or  even  wood  fiber,  provided  the  latter 
does  not  become  packed  down  so  as  to  prevent  the  air 
from  passing  freely.  Such  fibers  act  as  air-filters.  Reg- 
ular cleaning  or  renewal  of  the  fiber  protects  the  cylin- 
der from  wear.  In  a  general  way,  care  should  be 
taken,  before  fitting  both  the  gas  and  air  pipes,  to  tap 
the  pipes,  elbows,  and  joints  lightly  with  a  hammer  on 
the  outside  in  order  to  loosen  whatever  rust  or  sand 
may  cling  to  the  interior;  otherwise  this  foreign  matter 


MOUNTING    THE    AIR-PIPE  83 

may  enter  the  cylinder  and  cause  perturbations  in  the 
operation  of  the  engine.  Under  all  circumstances,  care 
should  be  taken  not  to  place  the  end  of  the  air-pipe 
under  the  floor  or  in  an  enclosed  space,  because  leakage 
may  occur,  due  to  the  bad  seating  of  the  air-valve,  there- 
by producing  a  mixture  which  may  explode  if  the 
flame  leaps  back,  as  we  shall  see  in  the  discussion  of 
suction  by  pipes  terminating  in  the  hollow  of  the  frame. 
On  the  other  hand,  sand  or  saw-dust  should  not  be 
sprinkled  on  the  floor. 

Exhaust. — For  the  exhaust,  cast-iron  or  drawn  pipes 
as  short  as  possible  should  be  used.  Not  only  the  power 
of  the  engine,  but  also  its  economic  consumption,  can  be 
markedly  affected  by  the  employment  of  long  and  bent 
pipes.  Resistance  to  the  exhaust  of  the  products  of 
combustion  not  only  causes  an  injurious  counter-pres- 
sure, but  also  prevents  the  clearing  of  the  cylinder  of 
burnt  gases,  which  contaminate  the  aspired  mixture 
and  rob  it  of  much  of  its  explosiveness.  The  necessity 
of  evacuating  the  cylinder  as  completely  as  possible  is, 
nevertheless,  not  always  reconcilable  with  local  sur- 
roundings. To  a  certain  extent,  the  objections  to  long 
exhaust-pipes  are  overcome  by  rigorously  avoiding  the 
use  of  elbows.  Gradual  curves  are  preferable.  In  the 
case  of  very  long  pipes  it  is  advisable  to  increase  their 
diameter  every  16  feet  from  the  exhaust.  The  exhaust- 
chest  should  be  placed  as  near  as  possible  to  the  engine; 
it  should  never  be  buried ;  for  the  joints  of  the  inlet  and 
outlet  pipes  of  the  exhaust-chest  should  be  easily  acces- 
sible, so  that  they  may  be  renewed  when  necessary.  The 


84      GAS-ENGINES    AND    PRODUCERS 

author  recommends  the  placing  of  the  exhaust-chest  in 
a  masonry  pit,  which  can  be  closed  with  a  sheet-metal 
cover.  For  engines  of  20  horse-power  and  upward, 
these  joints  should  be  entirely  of  asbestos.  Pipes 
screwed  directly  into  the  casting  are  liable  to  rust.  EX- 


FIG.  52. — Method  of  mounting  pipes. 

posed  as  they  are  to  the  steam  or  water  of  the  exhaust, 
they  cannot  be  detached. 

The  water,  which  results  from  the  combination  of 
the  hydrogen  of  the  gas  with  the  oxygen  of  the  air,  is 
deposited  in  most  cases  at  the  bottom  of  the  exhaust- 
chest.  It  is  advisable  to  fit  a  plug  or  iron  cock  in  the 
base  of  the  chest.  Alkaline  or  acid  water  will  always 
corrode  a  bronze  cock.  In  order  that  the  pipes  may 
not  also  be  attacked,  they  are  not  disposed  horizontally, 


THE   EXHAUST-PIPE  85 

but  are  given  a  slight  incline  toward  the  point  where 
the  water  is  drained  off.  If  pipes  of  some  length  be 
employed,  they  should  be  able  to  expand  freely  with- 
out straining  the  joints,  as  shown  in  the  accompany- 
ing diagram  (Fig.  52),  in  which  the  exhaust-chest 
rests  on  iron  rollers  which  permit  a  slight  displace- 
ment. 

For  the  sake  of  safety,  at  least  that  portion  of  the 
piping  which  is  near  the  engine  should  be  located  at  a 
proper  distance  from  woodwork  and  other  combustible 
material.  By  no  means  should  the  exhaust  discharge 
into  a  sewer  or  chimney,  even  though  the  sewer  or 
chimney  be  not  in  use;  for  the  unburnt  gases  may  be 
trapped,  and  dangerous  explosions  may  ensue  at  the 
moment  of  discharge. 

The  joints  or  threaded  sleeves  employed  in  assem- 
bling the  exhaust-pipe  should  be  tested  for  tightness. 
The  combined  action  of  the  moisture  and  heat  causes 
the  metal  to  rust  and  to  deteriorate  very  rapidly  at 
leaky  spots. 

When  several  engines  are  installed  near  one  another, 
each  should  be  provided  with  a  special  exhaust-pipe; 
otherwise  it  may  happen,  when  the  engines  are  all 
running  at  once,  that  the  products  of  combustion  dis- 
charged by  the  one  may  cause  a  back  pressure  detri- 
mental to  the  exhaust  of  the  next. 

It  is  possible  to  employ  a  pipe  common  to  all  the  ex- 
hausts if  the  pipe  starts  from  a  point  beyond  the  ex- 
haust-chests, in  which  case  Y-joints  and  not  T-joints 
are  to  be  used. 


86      GAS-ENGINES    AND    PRODUCERS 

The  manner  of  securing  the  pipes  to  walls  by  means 
of  detachable  hangers,  lined  with  asbestos,  is  shown  in 
a  general  way  in  the  accompanying  Fig.  53.  The 
object  of  this  arrangement  is  to  render  detachment 
easy  and  to  prevent  the  transmission  of  shocks  to  the 
masonry. 

The  precautions  to  be  taken  for  muffling  the  noise  of 
the  exhaust  will  be  discussed  later. 

The   end    of    the    exhaust-pipe    should    be    slightly 


FIG.  53. — Method  of  securing  pipes  to  walls. 

curved  down  in  order  to  prevent  the  entrance  of  rain. 
Exhaust-pipes  are  subjected  to  considerable  vibration, 
due  to  the  sudden  discharge  of  the  gases.  To  protect 
the  joints,  the  pipes  should  be  rigidly  fastened  in  place. 
Legal  Authorization. — In  most  countries  gas-en- 
gines may  be  installed  only  in  accordance  with  the 
provision  of  general  or  local  laws,  which  impose  cer- 
tain conditions.  These  laws  vary  with  different  local- 
ities, for  which  reason  they  are  not  discussed  here. 


CHAPTER  IV 

FOUNDATION  AND  EXHAUST 

THE  reader  will  remember  from  what  has  already 
been  said  that  a  gas-engine  is  a  motor  which,  more  than 
any  other,  is  subjected  to  forces,  suddenly  and  re- 
peatedly exerted,  producing  violent  reactions  on  the 
foundation.  It  follows  that  the  foundation  must  be 
made  particularly  resistant  by  properly  determining  its 
shape  and  size  and  by  carefully  selecting  the  material 
of  which  it  is  to  be  built. 

The  Foundation  Materials. — Well-hardened  brick 
should  be  used.  The  top  course  of  bricks  should  be 
laid  on  edge.  It  is  advisable  to  increase  the  stability 
of  the  foundation  by  longitudinally  elongating  it  to- 
ward the  base,  as  shown  in  the  accompanying  diagram 

(Fig-  54)- 
As   a  binding  material,   only  mortar  composed  of 

coarse'sand  or  river  sand  and  of  good  cement,  should 
be  used.  Instead  of  coarse  sand,  crushed  slag,  well- 
screened,  may  be  employed.  The  mortar  should  con- 
sist of  2/$  slag  and  ^  cement.  Oil  should  not  in  any 
way  come  into  contact  with  the  mortar;  it  may  perco- 
late through  the  cement  and  alter  its  resistant  qualities. 
As  in  the  construction  of  all  foundations,  care  should 

be  taken  to  excavate  down  to  good  soil  and  to  line  the 

87 


88      GAS-ENGINES    AND    PRODUCERS 

bottom  with  concrete,  in  order  to  form  a  single  mass  of 
artificial  stone.  A  day  or  two  should  be  allowed  for 
the  masonry  to  dry  out,  before  filling  in  around  it. 

When  the  engine  is  installed  on  the  ground  floor 
above  a  vaulted  cellar,  the  foundation  should  not  rest 


FIG.  54. — Method  of  building  the  foundation. 

directly  on  the  vault  below  or  on  the  joists,  but  should 
be  built  upon  the  very  floor  of  the  cellar,  so  that  it 
passes  through  the  planking  of  the  ground  floor  with- 
out contact. 

When  the  engine  is  to  be  installed  on  a  staging,  the 


THE   FOUNDATION 


89 


method  of  securing  it  in  place  illustrated  in  Fig.  55 
should  be  adopted. 

Although  a  foundation,  built  in  the  manner  de- 
scribed, will  fulfill  the  usual  conditions  of  an  industrial 
installation,  it  will  be  inadequate  for  special  cases  in 
which  trepidation  is  to  be  expected.  Such  is  the  case 
when  engines  are  to  be  installed  in  places  where,  ow- 
ing to  the  absence  of  factories,  it  is  necessary  to  avoid 


FIG.  55. — Elevated  foundation. 

all   nuisance,   such   as   noise,   trepidations,   odors,   and 
the  like. 

Vibration. — In  order  to  prevent  the  transmission  of 
vibration,  the  foundation  should  be  carefully  insulated 
from  all  neighboring  walls.  For  this  purpose  various 
insulating  substances  called  "  anti-vibratory  "  are  to  be 
recommended.  Among  these  may  be  mentioned  horse- 
hair, felt  packing,  cork,  and  the  like.  The  efficacy 
of  these  substances  depends  much  on  the  manner  in 
which  they  are  applied.  It  is  always  advisable  to  inter- 
pose a  layer  of  one  of  these  substances,  from  one  to  four 
inches  thick,  between  the  foundation  and  the  surround- 
ing soil,  the  thickness  varying  with  the  nature  of  the 


9o      GAS-ENGINES    AND    PRODUCERS 

material  used  and  the  effect  to  be  obtained.  Between 
the  bed  of  concrete,  mentioned  previously,  and  the 
foundation-masonry  and  between  the  foundation  and 
the  engine-frame,  a  layer  of  insulating  material  may 
well  be  placed.  Preference  is  to  be  given  to  substances 
not  likely  to  rot  or  at  least  not  likely  to  lose  their  in- 
sulating property,  when  acted  upon  by  heat,  moisture 
or  pressure. 

Here  it  may  not  be  amiss  to  warn  against  the  utiliza- 
tion of  cork  for  the  bottom  of  the  foundation ;  for  water 
may  cause  the  cork  to  swell  and  to  dislocate  the  founda- 
tion or  destroy  its  level. 

The  employment  of  the  various  substances  men- 
tioned does  not  entail  any  great  expense  when  the 
foundations  are  not  large  and  the  engines  are  light. 
But  the  cost  becomes  considerable  when  insulating  ma- 
terial is  to  be  employed  for  the  foundation  of  a  30  to  50 
horse-power  engine  and  upwards.  For  an  engine  of 
such  size  the  author  recommends  an  arrangement  as 
simple  as  it  is  efficient,  which  consists  in  placing  the 
foundation  of  the  engine  in  a  veritable  masonry  basin, 
the  bottom  of  which  is  a  bed  of  concrete  of  suitable 
thickness.  The  foundation  is  so  placed  that  the  lateral 
surfaces  are  absolutely  independent  of  the  supporting- 
walls  of  the  basin  thus  formed.  Care  should  be  taken 
to  cover  the  bottom  with  a  layer  of  dry  sand,  rammed 
down  well,  varying  in  thickness  with  each  case.  This 
layer  of  sand  constitutes  the  anti-vibratory  material  and 
confines  the  trepidations  of  the  engine  to  the  founda- 
tion. 


PREVENTION   OF  VIBRATION         91 

As  a  result  of  this  arrangement,  it  should  be  ob- 
served that,  being  unsupported  laterally,  the  founda- 
tion should  be  all  the  more  resistant,  for  which  reason 
the  base-area  and  weight  should  be  increased'  by  30  to 
40  per  cent.  The  expense  entailed  will  be  largely  off- 
set by  saving  the  cost  of  special  anti-vibratory  sub- 
stances. In  places  liable  to  be  flooded  by  water,  the 
basin  should  be  cemented  or  asphalted. 

When  the  engine  is  of  some  size  and  is  intended  for 
the  driving  of  one  or  more  dynamos  which  may  them- 
selves give  rise  to  vibrations,  the  dynamos  are  secured 
directly  to  the  foundation  of  the  engine,  which  is  ex- 
tended for  that  purpose,  so  that  both  machines  are  car- 
ried solidly  on  a  single  base. 

The  foregoing  outline  should  not  lead  the  proprie- 
tor of  a  plant  to  dispense  with  the  services  of  experts, 
whose  long  experience  has  brought  home  to  them  the 
difficulties  to  be  overcome  in  special  cases. 

It  should  here  be  stated,  as  a  general  rule,  that  the 
bricks  should  be  thoroughly  moistened  before  they  are 
laid  in  order  that  they  may  grip  the  mortar. 

After  having  been  placed  on  the  foundation  and 
roughly  trimmed  with  respect  to  the  transmission  de- 
vices, the  engine  is  carefully  leveled  by  means  of  hard- 
wood wedges  driven  under  the  base.  This  done,  the 
bolts  are  sealed  by  very  gradually  pouring  a  cement 
wash  into  the  holes,  and  allowing  it  to  set.  When  the 
holes  are  completely  filled  and  the  bolts  securely  fas- 
tened in  place,  a  shallow  rim,  or  edge  of  clay,  or  sand 
is  run  around  the  cast  base,  so  as  to  form  a  small  box 


92      GAS-ENGINES    AND    PRODUCERS 

or  trough,  in  which  cement  is  also  poured  for  the  pur- 
pose of  firmly  binding  the  engine  frame  and  founda- 
tion together.  When,  as  in  the  case  of  electric-light 
engines,  single  extra-heavy  fly-wheels  are  employed, 
provided  with  bearings  held  in  independent  cast  sup- 
ports, the  following  rule  should  be  observed  to  prevent 
the  overheating  due  to  unlevelness,  which  usually  oc- 
curs at  the  bushings  of  these  bearings :  That  part  of  the 
foundation  which  is  to  receive  such  a  support  should 
rest  directly  on  the  concrete  bed  and  should  be  rigidly 
connected  at  the  bottom  with  the  main  foundation. 
When  the  foundation  is  completely  blocked  up,  the  fly- 
wheel bearing  with  its  support  is  hung  to  the  crank- 
shaft; and  not  until  this  is  effected  is  the  masonry  at 
the  base  of  the  support  completed  and  rigidly  fixed  in 
its  proper  position. 

For  very  large  engines,  the  foundation-bolts  should 
be  particularly  well  sealed  into  the  foundation.  In 
order  to  attain  this  end  the  bricks  are  laid  around  the 
bolt-holes,  alternately  projected  and  retracted  as  showrn 
in  Fig.  54.  Broken  stone  is  then  rammed  down  around 
the  fixed  bolt;  in  the  interstices  cement  wash  is  poured. 

Air  Vibration,  etc. — Vibration  %  due  chiefly  to  the 
transmission  of  noises  and  the  displacement  of  air  by 
the  piston  should  not  be  confused  with  the  trepidations 
previously  mentioned. 

The  noise  of  an  engine  is  caused  by  two  dis- 
tinct phenomena.  The  one  is  due  to  the  transmit- 
ting properties  of  the  entire  solid  mass  constituting 
the  frame,  the  foundation,  and  the  soil.  The  other  is 


AIR   VIBRATION 


93 


due  to  vibrations  transmitted  to  the  air.  In  both  cases, 
in  order  to  reduce  the  noise  to  a  minimum,  the  moving 
parts  should  be  kept  nicely  adjusted,  and  above  all, 
shocks  avoided,  the  more  harmful  of  which  are  caused 
by  the  play  between  the  joint  at  the  foot  of  the  connect- 
ing-rod and  the  piston-pin,  and  between  the  head  of  the 
connecting-rod  and  the  crank-shaft. 

Although  smooth  running  of  the  engine  may  be  as- 
sured, there  is  always  an  inherent  drawback  in  the 
rapid  reciprocating  movement  of  the  piston.  In  large, 
single-acting  gas-engines,  a  considerable  displacement 
of  air  is  thus  produced.  In  the  case  of  a  forty  horse- 
power engine  having  a  cylinder  diameter  and  piston- 
stroke  respectively  of  13%  inches  and  2i3/5  inches,  it 
is  evident  that  at  each  stroke  the  piston  will  displace 
about  2  cubic  feet  of  air,  the  effect  of  which  will  be 
doubled  when  it  is  considered  that  on  the  forward 
stroke  back  pressure  is  created  and  on  the  return  stroke 
suction  is  produced. 

The  air  motion  caused  by  the  engine  is  the  more 
readily  felt  as  the  engine-room  is  smaller.  If  the  room, 
for  example,  be  9  feet  by  75  feet  by  8  feet,  the  volume 
will  be  i, 080  cubic  feet.  From  this  it  follows  that  the 
2  cubic  feet  of  air  in  the  case  supposed  will  be  alter- 
nately displaced  six  times  each  second,  which  means 
the. displacement  of  12  cubic  feet  at  short  intervals 
with'  an  average  speed  of  550  feet  per  minute.  Such 
vibrations  transmitted  to  halls  or  neighboring  rooms 
are  due  entirely. to  the  displacement  of  the  air. 

In  installations  where  the  air-intake  of  the  engine  is 


94      GAS-ENGINES    AND    PRODUCERS 

located  in  the  engine-room,  a  certain  compensation  is 
secured,  at  the  period  of  suction,  between  the  quantity 
of  air  expelled  on  the  forward  stroke  of  the  piston  and 
the  quantity  of  air  drawn  into  the  cylinder.  From  this 
it  follows  that  the  vibration  caused  by  the  movement 
of  the  air  is  felt  less  and  occurs  but  once  for  two  revolu- 
tions of  the  engine. 

This  phenomenon  is  very  manifest  in  narrow  rooms 
in  which  the  engine  happens  to  be  installed  near  glass 
windows.  By  reason  of  the  elasticity  of  the  glass,  the 
windows  acquire  a  vibratory  movement  corresponding 
in  period  with  half  the  number  of  revolutions  of  the 
engine.  It  follows  from  the  preceding  that,  in  order  to 
do  away  with  the  air  vibration  occasioned  by  the  piston 
in  drawing  in  and  forcing  out  air  in  an  enclosed  space, 
openings  should  be  provided  for  the  entrance  of  large 
quantities  of  air,  or  a  sufficient  supply  of  air  should 
be  forced  in  by  means  of  a  fan. 

The  author  ends  this  section  with  the  advice  that  all 

* 

pipes  in  general  and  the  exhaust-pipe  in  particular  be 
insulated  from  the  foundation  and  from  the  walls 
through  which  they  pass  as  well  as  from  the  ground, 
as  metal  pipes  are  good  conductors  of  sound  and  liable 
to  carry  to  some  distance  from  the  engine  the  sounds 
of  the  moving  parts. 

Exhaust  Noises. — Among  the  most  difficult  noises  to 
muffle  is  that  of  the  exhaust.  Indeed,  it  is  the  exhaust 
above  all  that  betrays  the  gas-engine  by  its  discharge  to 
the  exterior  through  the  exhaust-pipe.  The  most  com- 
monly employed  means  for  rendering  the  exhaust  less 


THE   EXHAUST-MUFFLER 


95 


perceptible  consists  in  extending  the  pipe  upward  as 
far  as  possible,  even  to  the  height  of  the  roof.  This  is 
an  easy  way  out  of  the  difficulty;  but  it  has  a  bad  effect 
on  the  operation  of  the  engine.  It  reduces  the  power 
generated  and  increases  the  consumption,  as  will  be  ex- 
plained in  a  special  paragraph. 

Expansion-boxes,    more   commonly   called   exhaust- 
mufflers,  considerably  deaden  the  noise  of  explosion  by 


FIG.  56. — Exhaust-muffler. 


the  use  of  two  or  three  successive  receptacles.  But  this 
remedy  is  attended  with  the  same  faults  that  mark  the 
use  of  extremely  long  pipes.  The  best  plan  is  to  mount 
a  single  exhaust-muffler  near  the  discharge  of  the  en- 
gine in  the  engine-room  itself,  where  it  will  serve  at 
least  the  purpose  of  localizing  the  sound. 

The  employment  of  pipes  of  sufficiently  large  cross- 
section  to  constitute  expansion-boxes  in  themselves  will 
also  muffle  the  exhaust.  A  more  complete  solution  of 
the  problem  is  obtained  by  causing  the  exhaust-pipe, 


96      GAS-ENGINES    AND    PRODUCERS 

after  leaving  the  muffler,  to  discharge  into  a  masonry 
trough  having  a  volume  equal  to  twelve  times  that  of 
the  engine-cylinder  (Fig.  56).  This  trough  should 
be  divided  into  two  parts,  separated  by  a  horizontal 
iron  grating.  Into  the  lower  part,  which  is  empty,  the 
exhaust-pipe  discharges;  in  the  upper  part,  paving- 
blocks  or  hard  stones  not  likely  to  crumble  with  the 
heat,  are  placed.  Between  this  layer  of  stones  and  the 
cover  it  is  advisable  to  leave  a  space  equal  to  the  first. 
Here  the  gases  may  expand  after  having  been  divided 
into  many  parts  in  passing  through  the  spaces  left  be- 
tween adjacent  stones.  The  trough  should  not  be 
closed  by  a  rigid  cover;  for,  although  efficient  muffling 
may  be  attained,  certain  disadvantages  are  neverthe- 
less encountered.  It  may  happen  that  in  a  badly  regu- 
lated engine,  unburnt  gases  may  be  discharged  into  this 
trough,  forming  an  explosive  mixture  which  will  be 
ignited  by  the  next  explosion,  causing  considerable 
damage.  Still,  the  explosion  will  be  less  dangerous 
than  noisy.  It  may  be  mentioned  in  passing  that  this 
disadvantage  occurs  rarely. 

A  second  arrangement  consists  in  superposing  the 
end  of  the  exhaust-pipe  upon  a  casing  of  suitable  size, 
which  casing  is  partitioned  off  by  several  perforated 
baffle-plates.  This  casing  is  preferably  made  of  wood, 
lined  with  metal,  so  that  it  will  not  be  resonant.  The 
size  of  the  casing,  the  number  of  partitions  and  their 
perforations,  and  the  manner  of  disposing  the  parti- 
tions have  much  to  do  with  the  result  to  be  obtained. 
Here  again  the  experience  of  the  expert  is  of  use. 


THE   EXHAUST-MUFFLER 


97 


Various  other  systems  are  employed,  depending  upon 
the  particular  circumstances  of  each  case.  Among 
these  systems  may  be  mentioned  those  in  which  the  pipe 
is  forked  at  its  end  to  form  either  a  yoke  (Fig.  57)  or 
a  double  curve,  each  branch  of  which  terminates  in  a 
muffler  (Fig.  58). 

It  should  be  observed  that,  under  ordinary  conditions, 
noises  heard  as  hissing  sounds  are  often  due  to  the 


Two  types  of  exhaust-mufflers. 

presence  of  projections,  or  to  distortion  of  the  pipes 
near  the  discharge  opening.  Consequently,  in  connect- 
ing the  pipes,  care  should  be  taken  that  the  joints  or 
seams  have  no  interior  projections.  Occasionally, 
water  may  be  injected  into  the  exhaust-muffler  in  order 
to  condense  the  vapors  of  the  exhaust,  the  result  being 
a  deadening  of  the  noises;  but  in  order  to  be  truly  effi- 
cient this  method  should  be  employed  with  discretion, 
for  which  reason  the  advice  of  an  expert  is  of  value. 


CHAPTER  V 

WATER  CIRCULATION 

CIRCULATION  of  water  in  explosion-engines  is  one  of 
the  essentials  of  their  perfect  operation.  Two  special 
cases  are  encountered.  In  the  one  the  jacket  of  the  en- 
gine is  supplied  with  running  water;  in  the  other,  reser- 
voirs are  employed,  the  circulation  being  effected 
simply  by  the  difference  in  specific  gravity  in  a  thermo- 
siphon  apparatus.  Coolers  are  also  used. 

Running  Water. — A  water-jacket  fed  from  a  con- 
stant source  of  running  water,  such  as  the  water  mains 
of  a  town,  is  certainly  productive  of  the  best  results,  the 
supply,  moreover,  being  easily  regulated;  but  the  sys- 
tem is  not  widely  used  because  the  water  runs  away  and, 
is  entirely  lost.  If  running  water  be  employed,  the  out- 
let of  trie  jacket  is  so  disposed  that  the  water  gushes  out 
immediately  on  leaving  the  cylinder,  and  that  the  flow 
is  visible  and  accessible,  in  order  that  the  temperature 
may  be  tested  by  the  hand.  Apart  from  the  relatively 
great  cost  of  water  in  towns,  the  use  of  running  water 
is  objectionable  on  account  of  its  chemical  composi- 
tion. Though  it  may  be  clear  and  limpid,  it  frequently 
contains  lime  salts,  carbonates,  sulphates,  and  silicates 
which  are  precipitated  by  reason  of  the  sudden  change 

of  temperature  to  which  the  water  is  subjected  as  .it 

98 


IMPURE   WATER  99 

comes  into  contact  with  the  walls  of  the  cylinder.  That 
part  of  the  water-jacket  surrounding  the  head  or  explo- 
sion-chamber, where  the  temperature  is  necessarily  the 
highest,  becomes  literally  covered  with  calcareous  in- 
crustations, which  are  the  more  harmful  because  they 
are  bad  conductors  of  heat  and  because  they  reduce  and 
even  obs.truct  the  passage  exactly  at  the  point  where  the 
water  must  circulate  most  freely  to  do  any  good.  If  the 
circulating  water  be  pumped  into  the  jacket,  it  is  pref- 
erable, wherever  possible,  to  use  cistern  water,  which  is 
not  likely  to  contain  lime  salts  in  suspension.  If  river 
water  be  used,  it  should  be  free  from  the  objections 
already  mentioned,  which  are  all  the  more  grave  if  the 
water  be  muddy,  as  sometimes  happens.  The  water- 
jacket  can  be  easily  freed  from  all  non-adhering  de- 
posits by  flushing  it  periodically  through  the  medium 
of  a  conveniently  placed  cock.  It  is  always  preferable 
to  pass  the  water  through  a  reservoir  where  its  impuri- 
ties can  settle,  before  it  flows  to  the  cylinder.  In  the 
case  considered,  the  water  usually  has  an  average  tem- 
perature of  54  to  60  degrees  F.,  under  which  condition 
the  hourly  flow  should  be  at  least  $y2  gallons  per  horse- 
power per  hour,  the  temperature  rising  at  the  outlet- 
pipe  of  the  cylinder  to  140  and  158  degrees  F.,  which 
should  not  be  surpassed.  However,  in  engines  working 
with  high  compression,  104  to  122  degrees  F.  should 
not  be  exceeded. 

If  the  water-jacket  be  fed  by  a  reservoir,  it  is  essen- 
tial that  the  reservoir  comply  with  the  following  con- 
ditions: 


ioo    GAS-ENGINES    AND    PRODUCERS 


In  horizontal  engines  the  water-inlet  is  always 
located  in  the  base  of  the  cylinder,  while  the  outlet  is 
located  at  the  top.  By  providing  the  inlet-pipe  extend- 
ing to  the  cylinder  with  a  cock,  the  circulation  of  water 
can  be  regulated  to  correspond  with  the  work  per- 
formed by  the  engine.  Another  cock  at  the  end  of  the 
outlet-pipe  near  the  reservoir  serves,  in  conjunction 


FIG.  59. — Thermo -syphon  cooling  system. 

with  the  first,  to  arrest  the  circulating  water.  When  the 
weather  is  very  cold  or  when  the  cylinder  must  be 
repaired,  these  two  cocks  may  be  closed,  and  the  pipe 
and  water-jacket  of  the  cylinder  drained  by  means  of 
the  drain-cock  V  (Fig.  59),  mounted  at  the  inlet  of  the 
engine's  water-jacket.  In  order  that  the  pressure  of 
the  atmosphere  may  not  prevent  the  flowing  of  the 
water,  the  highest  part  of  the  pipe  is  provided  with  a 
small  tube,  T,  communicating  with  the  atmosphere. 
On  account  of  the  importance  of  preventing,  losses 


WATER-TANKS 


101 


of  the  charge  in  the  pipes  the  author  recommends  the 
utilization  of  sluice-valves  of  the  type  shown  in  Fig. 
60,  instead  of  the  usual  cone  or  plug  type. 


FIG.  60. — Vanne  sluice-cock. 

Water-Tanks. — The  reservoir  is  mounted  in  such  a 
way  that  its  base  is  flush  with  the  top  of  the  cylinder;  it 
should  be  as  near  as  possible  to  the  cylinder  in  order  to 
obviate  the  use  of  long  inlet  and  return  pipes.  This 
fact,  however,  does  not  necessarily  render  it  advisable 
to  place  the  reservoir  in  the  engine-room;  for  such  a 
disposition  is  doubly  disadvantageous  in  so  far  as  it 
does  not  permit  a  sufficiently  rapid  cooling  of  the  cir- 
culating water  by  reason  of  the  high  temperature  of  the 


102    GAS-ENGINES    AND    PRODUCERS 

surrounding  air,  and  in  so  far  as  it  is  liable  to  cause  the 
formation  of  vapors  which  injuriously  affect  the  en- 
gine. Consequently,  the  reservoir  should  be  placed  in 
as  cool  a  place  as  possible,  preferably  even  in  the  open 
air;  for  the  water  is  not  likely  to  freeze,  except  when 
it  has  been  allowed  to  stand  for  a  considerable  time. 
The  reservoir  should  be  left  uncovered  so  as  to  facili- 
tate cooling  by  the  liberation  of  the  vapors  formed  on 
the  surface  of  the  water. 

Circulation  being  effected  solely  by  the  difference 
in  specific  gravity  or  density  between  the  warmer  water 
emerging  from  the  cylinder  and  the  cooler  water  which 
flows  in  from  the  reservoir,  the  slightest  obstruction 
will  impede  the  flow.  Hence,  the  cross-section  of  the 
pipes  should  not  be  less  than  that  of  the  inlet  and  outlet 
openings  of  the  cylinder  of  the  engine.  Good  circula- 
tion cannot  be  attained  if  the  water  must  overcome  in- 
clines or  obstacles  in  the  pipes  themselves.  Instead  of 
elbows,  long  curves  of  great  radius,  limited  to  the 
smallest  possible  number,  should  be  employed.  This  is 
particularly  true  of  the  return-pipe  extending  from 
the  cylinder  back  to  the  reservoir.  For  this  pipe  a 
minimum  incline  of  10  to  15  per  cent,  should  be  al- 
lowed, in  order  that  the  water  may  run  up  into  the 
reservoir.  The  height  of  the  water  in  the  reservoir 
should  be  from  2  to  4  inches  above  the  discharge  of  the 
return-pipe.  In  order  to  maintain  this  level  it  is  advis- 
able to  use  some  automatic  device  such  as  a  float-valve, 
in  which  case  the  reservoir  should  not  be  allowed  to 
become  too  full. 


WATER-TANKS 


103 


The  size  of  a  reservoir  is  determined  by  the  engine; 
it  should  be  large  enough  to  enable  the  engine  to  run 


FIG.  61. — Correct  arrangement  of  tanks  and  piping. 

smoothly  at  its  maximum  load  for  several  hours  con- 
secutively.     Under    these    conditions,    the    reservoir 


104    GAS-ENGINES    AND    PRODUCERS 


should  have  a  capacity  of  45  to  55  gallons  per  horse- 
power for  engines  with  "  hit-and-miss  "  admission,  and 
55  to  65  gallons  for  engines  controlled  by  variable  ad- 
mission. It  is  not  advisable  to  employ  reservoirs  hav- 


FiG.  62. — Incorrect  arrangement  of  tanks  and  piping. 

ing  a  capacity  of  more  than  330  to  440  gallons,  the 
usual  diameter  being  about  3  feet. 

If  the  power  of  the  engine  be  such  that  several 
reservoirs  are  necessary,  then  the  reservoirs  should  be 
connected  in  such  a  manner  that  the  top  of  the  first 
communicates  with  the  bottom  of  the  next  and  so  on, 


CONNECTION   OF  TANKS  105 

the  first  reservoir  receiving  the  water  as  it  comes  from 
the  cylinder  (Fig.  61). 

Intercommunication  of  the  reservoirs  by  means  of  a 
common  top  tube  (a)  is  objectionable;  and  simul- 
taneous intercommunication  at  top  and  bottom  (a  and 
b)  is  ineffective,  so  far  as  one  of  the  reservoirs  is  con- 
cerned (Fig.  62) . 

The  reservoirs  are  true  thermo-siphons.  Conse- 
quently the  water  should  be  methodically  circulated; 
in  other  words,  the  hottest  water,  flowing  from  the  en- 


FIG.  63. — Tanks  connected  by  inclined  pipes. 

gine  into  the  top  of  the  first  reservoir  and  having,  for 
example,  a  temperature  of  104  degrees  F.,  is  cooled  off 
to  86  degrees  F.  and  drops  to  the  bottom  of  the  reser- 
voir, thence  to  be  driven,  at  a  temperature  sensibly 


106    GAS-ENGINES    AND    PRODUCERS 

equal  to  86  degrees  F.,  to  the  second  reservoir,  where  a 
further  cooling  of  18  degrees  F.  takes  place.  In  pass- 
ing on  to  the  following  reservoirs  the  temperature  is 
still  further  lowered,  until  the  water  finally  reaches  its 
minimum  temperature,  after  which  it  flows  back  to  the 
engine-cylinder. 

In  order  to  effect  this  cooling,  the  reservoirs  can  be 
connected  in  several  ways.  The  most  common  method, 
as  shown  in  Fig.  63,  consists  in  connecting  the  reser- 
voirs by  oblique  pipes.  This  is  open  to  criticism,  how- 


FiG.  64. — Circulating  pump  with  by-pass. 

ever,  since  leakage  occurs,  caused  by  the  employment 
of  elbows  which  retard  the  circulation.  A  less  cum- 
brous and  more  efficient  method  of  connection  consists 
in  joining  the  reservoirs  by  a  single  pipe  at  the  top,  as 
shown  in  Fig.  61 ;  but  care  must  be  taken  to  extend  this 
pipe  at  the  point  of  its  entrance  into  the  adjoining 
reservoir  by  means  of  a  downwardly  projecting  exten- 
sion, or  to  fit  its  discharge-end  with  a  box,  closed  by  a 
single  partition,  open  at  the  bottom. 


PREVENTION   OF   INCRUSTATION      107 

In  order  to  prevent  incrustation  of  the  water-jacket 
surrounding  the  cylinder,  a  pound  of  soda  per  17  cubic 
feet  of  the  reservoir  capacity  is  monthly  introduced, 
and  the  jacket  flushed  weekly  by  a  cock  conveniently 
mounted  near  the  cylinder  (Fig.  59).  The  jacket  is 
thus  purged  of  calcareous  sediments,  which  are  pre- 
vented by  the  soda  from  adhering  to  the  metal.  The 
flushing-cock  mentioned  also  serves  to  drain  the  water- 
jacket  of  the  cylinder  in  case  of  intense  or  persistent 
cold,  which  would  certainly  freeze  the  water  in  the 
jacket,  thereby  cracking  the  cylinder  or  the  exposed 
pipes. 

In  order  to  regulate  the  circulation  of  the  water  in 
accordance  with  the  work  performed  by  the  engine,  a 
cock  should  be  fitted  to  the  water  supply  pipe  at  a  con- 
venient place. 

In  engines  of  large  size,  driven  at  full  load  for  long 
periods,  cooling  by  natural  circulation  is  often  in- 
adequate. In  such  cases,  circulation  is  quickened  by  a 
small  rotary  or  reciprocating  pump,  driven  from  the 
engine  itself  and  fitted  with  a  by-pass  provided  with  a 
cock.  This  arrangement  permits  the  renewal  of  the 
natural  thermo-siphon  circulation  in  case  of  accident 
to  the  pump  (Fig.  64). 

Coolers. — The  arrangement  which  is  illustrated  in 
Fig.  65,  and  which  has  the  merit  of  simplicity,  will  be 
found  of  service  in  cooling  the  water.  It  comprises  a 
tank  B  surmounted  by  a  set  of  trays  E,  formed  of  frames 
to  which  iron  rods  are  secured,  spaced  i  to  2  feet  apart, 
so  as  to  form  superimposed  series  separated  by  ij4  to 


io8    GAS-ENGINES    AND    PRODUCERS 

21/;  feet.  On  these  trays  bundles  of  tree  branches  are 
placed.  The  cold  water  at  the  bottom  of  the  tank  is 
forced  by  the  pump  P  into  the  water-jacket,  from 
which  it  emerges  hot,  and  flows  through  the  pipe  Ty 


FIG.  65. — Water-cooler  in  which  tree  branches  are  employed. 

which  ends  in  a  sprinkler  G,  formed  of  communicat- 
ing tubes  and  perforated  with  a  sufficient  number  of 
holes  to  enable  the  water  to  fall  upon  the  trays  in  many 
drops.  Thus  finely  divided,  the  water  falls  from  one 
tray  to  another,  retarded  as  it  descends  by  the  bundles 


COOLERS 


109 


of  tree  branches.  It  finally  reaches  the  tank  in  a  very 
cold  condition  and  is  then  ready  to  be  pumped  to  the 
engine.  Birch  branches  are  to  be  preferred  on  account 
of  their  tenuity. 

Great  care  should  be  taken  to  cover  the  tank  with 
a  sheet-metal  closure  in  order  to  prevent  twigs  and 


FIG.  66. — Fan-cooler. 

foreign  bodies  from  entering  and  from  being  drawn 
into  the  pump. 

In  the  following  table  the  dimensions  of  an  operative 
apparatus  of  this  kind  are  given, — an  apparatus,  more- 
over, that  may  be  constructed  of  wood  or  of  iron: — 


T~nlr 

Horse- 

Volume in 

Height  of 

Pump  —  Capacity 

power. 

cubic  ft. 

Case. 

Height. 

trav-base. 

in  gals,  per  min. 

30 

105 

4-9'  x  4-9' 

4.4' 

6.6' 

16.71 

40 

154 

5.2'  x  5.2' 

5.6' 

7-4' 

18.69 

50 

190 

5.7'  x  5.7' 

6.4' 

8.1' 

21.99 

75 

350 

6.6'  x  6.6' 

8.1' 

9.1' 

100 

490 

7.4'  x  7.4' 

9.1' 

9.1' 

43-98 

no    GAS-ENGINES    AND    PRODUCERS 

In  order  that  the  water  may  not  drop  to  one  side,  the 
base  of  the  apparatus  should  be  made  10  to  12  inches 
less  in  width  than  the  tank. 

The  size  of  these  apparatus  may  be  considerably  re- 
duced by  constructing  them  in  the  form  of  closed  chests, 
into  the  bottom  of  which  air  may.be  injected  by  means 
of  fans  in  order  to  accelerate  cooling  (Fig.  66). 


CHAPTER   VI 

LUBRICATION 

LUBRICATION  is  a  subject  that  should  be  studied  by 
every  gas-engine  user.  So  far  as  the  piston  is  con- 
cerned it  is  a  matter  of  the  utmost  importance.  The 
piston  does  its  work  under  very  peculiar  conditions. 
It  is  driven  at  great  linear  velocities;  and  it  is,  more- 
over, subjected  to  high  temperatures  which  have  noth- 
ing in  common  with  good  lubrication  if  care  be  not 
exercised. 

The  piston  is  the  essential,  vital  element  of  an  en- 
gine. Upon  its  freedom  from  leakage  depends  the 
maintenance  of  a  proper  compression,  and,  conse- 
quently, the  production  of  power  and  economical  con- 
sumption. As  it  travels  forward  and  as  it  recedes  from 
the  explosion-chamber,  it  uncovers  more  and  more  of 
the  frictional  surface  constituting  the  interior  wall  of 
the  cylinder.  This  surface,  as  a  result,  is  regularly 
brought  into  contact  with  the  ignited,  expanding  gases 
after  each  explosion.  For  this  reason  the  oil  which 
covers  the  wall  is  constantly  subjected  to  high  tempera- 
tures, by  which  it  is  likely  to  be  volatilized  and  burned. 
Therefore,  the  first  condition  to  be  fulfilled  in  properly 
lubricating  the  piston  is  a  constant  and  regular  sup- 
ply of  oil. 


TIT 


ii2    GAS-ENGINES    AND    PRODUCERS 

Quality  of  Oils. — For  cylinder  lubrication  only  the 
very  best  oils  should  be  used;  perfect  lubrication  is  of 
such  importance  that  cost  should  not  be  considered. 
Besides,  the  surplus  oil  which  is  usually  caught  in  the 
drip-pan  is  by  no  means  lost.  After  having  been  fil- 
tered it  can  be  used  for  lubricating  the  bearings  of  the 
crank,  the  cam-shaft,  and  like  parts. 

Cylinder-oil  should  be  exceedingly  pure,  free  from 
acids,  and  composed  of  hydrocarbons  that  leave  no  resi- 
due after  combustion.  Only  mineral  oils,  therefore, 
are  suitable  for  the  purpose.  Those  oils  should  be 
selected  which,  with  a  maximum  of  viscosity,  are 
capable  of  withstanding  great  heat  without  volatilizing 
or  burning.  The  point  at  which  a  good  cylinder-oil 
ignites  should  not  be  lower  than  535  degrees  F. 

Whether  an  oil  possesses  this  essential  quality  is 
easily  enough  ascertained  in  practice  without  resort- 
ing to  laboratory  tests.  All  that  is  necessary  is  to  heat 
the  oil  in  a  metal  vessel  or  a  porcelain  dish.  In  order 
that  the  temperature  may  be  uniform  the  vessel  is 
shielded  from  the  direct  flame  by  interposing  a  piece 
of  sheet  metal  or  a  layer  of  dry  sand.  As  soon  as  gases 
begin  to  arise  a  lighted  match  is  held  over  the  oil. 
When  the  gases  are  ignited  the  thermometer  reading  is 
taken,  the  instrument  being  immersed  in  the  oil.  The 
temperature  recorded  is  that  corresponding  with  the 
point  of  ignition. 

For  cylinder  lubrication  American  mineral  oil  is 
preferable  to  Russian  oil.  The  specific  gravity  should 
lie  somewhere  between  .886  and  .889  at  70  degrees  F. 


CYLINDER-OILS 


M-3 


Oil  of  this  quality  begins  to  evaporate  at  about  365 
degrees  F.  Ignition  occurs  at  535  degrees  F.  The 
point  of  complete  combustibility  lies  between  625  and 
645  degrees  F.  Oil  of  this  quality  solidifies  at  39  or 
41  degrees  F.  Its  color  is  a  reddish  yellow  with  a 
greenish  fluorescence.  Compared  with  water  its  degree 
of  viscosity  lies  between  11.5  and  12.5  at  a  tempera- 
ture of  140  degrees  F. 

Before  lubricating  other  parts  of  the  engine  with 
oil  that  has  been  used  for  the  piston,  heavy  particles 
and  foreign  matter,  such  as  dust,  bearing  incrusta- 
tions, and  the  like,  should  be  filtered  out.  The  piston- 
pivot  and  the  connecting-rod  head  are  preferably 
lubricated  with  fresh  oil,  because  their  constant  move- 
ment renders  inspection  difficult  and  the  control  of 
lubrication  irksome.  A  good,  industrial  mineral  oil 
of  usual  market  quality  will  be  found  satisfactory. 

In  order  to  bring  home  the  importance  of  employ- 
ing good  cylinder-oil  and  of  proper  lubrication  the 
author  can  only  state  that  in  his  personal  experience  he 
has  frequently  detected  losses  varying  from  10  to  15 
per  cent,  in  the  power  developed  by  engines  poorly 
lubricated. 

Types  of  Lubricators. — Among  the  more  common 
apparatus  employed  for  automatically  lubricating  the 
cylinder,  the  author  mentions  an  English  oiler  of  the 
type  pictured  in  Fig.  67  which  is  driven  simply  by 
a  belt  from  the  intermediary  shaft,  and  which  rotates 
the  pulley  P  secured  on  the  shaft  a  of  the  apparatus, 
at  a  very  slow  speed.  The  shaft  a  is  provided  at  its 


n4    GAS-ENGINES    AND    PRODUCERS 

end  with  a  small  crank,  from  which  a  small  iron  arm 
/  is  suspended,  which  arm  dips  in  the  oil  contained  in 
the  cup  G  of  the  oiler.  When  the  shaft  a  is  turned  this 
arm,  as  it  sweeps  through  the  oil-bath,  collects  a  certain 
quantity  of  oil  which  it  deposits  on  the  collector 
b.  From  this  spindle  the  oil  passes  through  an  out- 
let-pipe opening  into  the  bottom  of  the  oiler,  and 
thence  to  the  cylinder.  The  entire  apparatus  is  closed 


FIG.  67. — An  automatic  English  oiler. 
i 

by  a  cover  D  which  can  be  easily  removed  in  order  to 
ascertain  the  quantity  of  oil  still  remaining  in  the 
apparatus.  Many  other  systems  are  utilized  which, 
like  the  one  that  has  been  described,  enable  the  feed  to 
be  controlled.  Often  small  force-pumps  are  employed 
as  cylinder-lubricators.  Whatever  may  be  the  type 
selected,  preference  should  be  given  to  that  in  which 
the  feed  is  visible  (Fig.  68). 

If  the  oil  be  fed  under  pressure  the  cylinder  is  more 
constantly  lubricated.  Pressure-lubricators  are  nowa- 
days widely  used  on  large  engines.  It  is  advisable  to 


OIL-PUMPS  ii  r 

f  j 

add  a  little  salt  to  the  water  contained  in  sight-feed 
lubricators  so  that  the  drop  of  oil  is  easily  freed. 

These  oil-pumps  are  provided  with  small  check- 
valves  at  their  outlets  as  well  as  at  the  inlets  of  cylin- 
ders. In  order  that  pressure-lubricators  may  operate 
perfectly  they  should  be  regularly  inspected  and  the 
check-valves  ground  from  time  to  time. 

The  lubrication  of  the  crank-shaft  and  of  the  two 
connecting-rod  heads  should  receive  every  attention. 


FIG.  68. — Sight-feed  lubricating-pump. 

Lubricating  devices  should  be  employed  which, 
besides  being  efficient,  do  not  necessitate  the  stopping 
of  the  engine  in  order  to  oil  the  bearings.  The  foot  of 
the  connecting-rod  at  the  point  where  it  is  pivoted  to 
the  piston  is  generally  lubricated  with  cylinder-oil 
which  is  supplied  by  a  tube  mounted  in  the  proper 
place  across  the  piston-wall  (Fig.  69).  This  ar- 
rangement may  be  adequate  enough  for  small  engines; 
but  it  is  not  sufficiently  sure  for  engines  of  considerable 
size.  An  independent  lubricating  system  should  be 
employed,  lubrication  being  effected  either  by  a 


n6    GAS-ENGINES    AND    PRODUCERS 

splasher  mounted  in  front  of  the  cylinder  or  by  a  lubri- 
cator secured  to  the  connecting-rod  by  which  the  pivot 
is  lubricated  through  the  medium  of  a  small  tube  sup- 
plying special  oil  (Fig.  21).  The  head  of  the  con- 
necting-rod where  it  meets  the  crank,  must  also  be 
carefully  lubricated  because  of  the  important  nature 
of  the  work  which  it  must  perform,  and  because  of  the 
shocks  to  which  it  is  subjected  at  each  explosion.  For 


FIG.  69. — Method  of  oiling  the.  piston  and  end  of  the  connecting-rod. 

motors  of  high  power  the  system  which  seems  to  give 
most  satisfactory  results  is  that  illustrated  in  Fig.  70. 
The  arrangement  there  shown  consists  of  an  annular 
vessel  secured  at  one  side  of  the  crank  and  turning  con- 
centrically on  its  axis ;  the  vessel  being  connected  with  a 
long  tube  extending  into  a  channel  formed  in  the  crank 
and  discharging  at  the  surface  of  the  crank-pin  within 
the  bearing  at  the  head  of  the  connecting-rod.  An 
adjustable  sight-feed  lubricator  conducts  the  oil  along 
a  pipe  to  the  vessel.  Turning  with  the  shaft,  the  ves- 


CRANK-SHAFT    LUBRICATION        117 

sel  retains  the  oil  in  the  periphery  so  that  the  feed  in 
the  previously  mentioned  channel  in  the  connecting- 
rod  head,  is  constant. 

The  main  crank-shaft  bearings  are  more  easily  lubri- 
cated. Among  the  systems  commonly  used  with  good 
results  may  be  mentioned  that  shown  in  Fig.  71,  in 
which  the  half  section  represents  a  small  tube  starting 


FIG.  70. — Method  of  oiling  the  crank-shaft. 

from  the  bearing  and  terminating  in  the  interior  of  an 
oil  recess  or  reservoir  cast  integrally  with  the  bearing- 
cap.  This  reservoir  is  filled  up  to  the  level  of  the  tube 
opening.  A  piece  of  cotton  waste  held  on  a  small  iron 
wire  is  inserted  in  the  tube,  part  of  the  cotton  being 
allowed  to  hang  down  in  the  reservoir.  This  cotton 
serves  as  a  kind  of  siphon  and  feeds  the  bearing  by 
capillary  attraction  with  a  constant  quantity  of  oil,  the 
supply  being  regulated  by  varying  the  thickness  of  the 


n8    GAS-ENGINES    AND    PRODUCERS 

cotton.  When  the  motor  is  stopped,  the  cotton  should 
be  removed  in  order  that  oil-feeding  may  not  use- 
lessly continue.  Glass,  sight-feed  lubricators  with 
stop-cocks,  are  very  often  used  on  crank-shafts.  They 
are  cleaner  and  much  more  easily  regulated.  Of  all 
shaft-bearing  lubricators,  those  which  are  most  to  be 
recommended  are  of  the  revolving- ring  type  (Fig. 
72).  They  presuppose,  however,  bearings  of  large 


FIG.  71. — Cotton-waste  lubricator. 

size  and  a  special  arrangement  of  bushings  which  ren- 
ders their  application  somewhat  expensive.  Further- 
more, the  revolving-ring  system  can  hardly  be  used  in 
connection  with  engines  of  less  than  20  horse-power. 
Since  the  system  is  applied  almost  exclusively  to 
dynamo-shafts,  it  need  not  here  be  described  in  detail. 
As  its  name  indicates,  it  consists  of  a  metal  ring  having 
a  diameter  larger  than  that  part  of  the  shaft  from 
which  it  is  suspended  and  by  which  it  is  rotated.  The 
lower  part  of  the  ring  is  immersed  in  an  oil  bath  so 


REVOLVING-RING    OILERS 


119 


that  a  certain  quantity  of  lubricant  is  continually  trans- 
ferred to  the  shaft. 

The  revolving  ring  bearing  should  be  fitted  with  a 
drain-cock  and  a  glass  tube  in  order  to  control  the 
level  of  the  oil  in  the  bearing. 

Many  manufacturers  have  adopted  lubricating  de- 


FIG.  72. — Ring  type  of  bearing  oiler. 

vices  for  valve-stems,  and  especially  for  exhaust-valves. 
The  system  adopted  consists  of  a  small  tube  curved  in 
any  convenient  direction  and  discharging  in  the  stem- 
guide.  The  free  end  is  provided  with  a  plug.  A  few 
drops  of  petroleum  are  introduced  once  or  twice  a  day. 
The  lubrication  of  an  engine  entails  certain  difficul- 
ties which  are  easily  overcome.  One  of  these  is  the 


120    GAS-ENGINES    AND    PRODUCERS 

splashing  of  oil  by  the  connecting-rod  head.  In  order 
that  this  splashed  oil  may  be  collected  in  the  base 
of  the  engine  a  suitably  curved  sheet-metal  guard  is 
mounted  over  the  crank.  A  more  serious  difficulty 
is  presented  when  the  oil  from  a  crank-bearing  finds 
its  way  to  the  hub  of  the  fly-wheel,  whence  it  is  driven 
by  the  centrifugal  force  to  the  rim.  The  oil  is  not  only 
splashed  against  the  walls  of  the  engine-room,  but  it 
also  destroys  the  adhesion  of  the  belt  if  the  fly-wheel 


FIG.  73. — Shaft  with  oil-guard. 

be  employed  as  a  pulley.  In  order  to  overcome  this 
objection  the  oil  is  prevented  from  spreading  along  the 
shaft  by  means  of  a  circular  guard  (Fig.  73)  mounted 
on  that  portion  of  the  shaft  toward  the  interior  of  the 
bearing. 

The  problem  of  lubrication  is  of  particular  im- 
portance if  the  engine  is  driven  for  several  days  at 
a  time  without  a  stop.  This  happens  in  the  case  of 
mill  and  shop  engines.  Lubricators  of  large  volume 
or  lubricators  which  can  be  readily  filled  without  stop- 
ping the  engine  should  be  employed. 


CHAPTER   VII 

THE  CONDITIONS  OF   PERFECT  OPERATION 

General  Care. — Gas-engines,  as  well  as  most  ma- 
chines in  general,  should  be  kept  in  perfect  condition. 
Cleanliness,  even  in  the  case  of  parts  of  secondary  im- 
portance, is  indispensable.  Unpainted  and  polished 
surfaces  such  as  the  shaft  of  the  engine,  the  distribut- 
ing cam-shafts,  the  levers,  the  connecting-rod  and  the 
like,  should  be  kept  in  a  condition  equal  to  that  when 
they  were  new.  The  absence  of  all  traces  of  rust  or 
corrosion  in  these  parts  affords  sufficient  evidence  of 
the  care  taken  of  the  invisible  members  such  as  the 
piston,  the  valves,  ignition  devices,  and  the  like. 

Lubrication. — The  rubbing  surfaces  of  a  gas-engine 
should  be  regularly  and  perfectly  lubricated.  The 
absence  of  lost  motion  and  backlash  in  the  bearings, 
guides,  and  joints  is  of  particular  importance  not  only 
because  of  its  influence  on  steady  and  silent  running, 
but  also  on  the  power  developed  and  on  the  consump- 
tion. As  we  have  already  seen  in  the  chapter  on  lubri- 
cation, a  special  quality  of  oil  should  be  employed  *for 
the  lubrication  of  the  cylinder.  The  feed  of  the  lubri- 
cator supplying  this  most  vital  part  of  the  engine  is  so 
regulated  that  it  meets  the  actual  requirements  with 
the  utmost  nicety  possible.  In  a  subsequent  chapter, 


121 


122    GAS-ENGINES    AND    PRODUCERS 

in  which  faulty  operation  will  be  discussed,  it  will  be 
shown  how  too  much  and  too  little  oil  may  cause  seri- 
ous trouble. 

Tightness  of  the  Cylinder.— The  amount  of  power 
developed  depends  principally  on  the  degree  of  com- 
pression to  which  the  explosive  mixture  is  subjected. 
The  economical  operation  of  the  engine  depends  in 
general  upon  perfect  compression.  It  is,  therefore, 
necessary  to  keep  those  parts  in  good  order  upon  which 
the  tightness  of  the  cylinder  depends.  These  parts  are 
the  piston,  the  valves,  and  their  joints,  and  the  igni- 
tion devices  whether  they  be  of  the  hot-tube  or  elec- 
trical variety.  In  order  to  prevent  leakage  at  the  pis- 
ton, the  rings  should  be  protected  from  all  wear.  It 
is  of  the  utmost  importance  that  the  surfaces  both  of 
the  piston  and  of  the  cylinder,  be  highly  polished  so 
that  binding  cannot  occur.  In  cleansing  the  cylinder, 
emery  paper  or  abrasive  powder  should  not  be  em- 
ployed; for  the  slightest  particle  of  abrasive  between 
the  surfaces  in  contact  will  surely  cause  leakage.  The 
oil  and  dirt,  which  is  turned  black  by  friction  and 
which  may  adhere  to  the  piston  rings,  should  be 
washed  away  with  petroleum.  Similarly  the  other 
parts  of  the  cylinder  should  be  cleaned  to  which  burnt 
oil  tends  to  adhere. 

Valve-Regrinding. — The  valves  should  be  regu- 
larly ground.  Even  in  special  cases  where  they  may 
show  no  trace  of  rapid  wear  they  should  be  removed 
at  least  every  month.  In  order  to  avoid  any  accident, 
care  should  be  taken  in  adjusting  the  valves  after  the 


RA7T 

or  T  M  e 

UNIVERSITY 

VALVE-GRINDING 


cap  has  been  unbolted  not  to  introduce  a  candle  or  a 
lighted  match  either  in  the  valve-chambers  or  in  the 
cylinder,  without  first  closing  the  gas-cock.  Further- 
more, a  few  turns  should  be  given  to  the  engine,  in 
order  to  drive  out  any  explosive  mixture  that  may  still 
remain  in  the  cylinder  or  the  connected  passages.  The 
exhaust-valve,  by  reason  of  the  high  temperature  to 
which  the  disk  and  the  seat  are  subjected,  should  re- 
ceive special  attention.  The  valve  should  be  ground 
on  its  seat  every  two  or  three  months  at  least,  depend- 
ing upon  the  load  of  the  engine. 

Bearings  and  Crosshead. — The  bushings  of  the  en- 
gine shaft  should  always  be  held  tightly  in  place.  The 
looseness  to  which  they  are  liable,  particularly  in  gas- 
engines  on  account  of  the  sharp  explosions,  tends  to 
unscrew  the  nuts  and  to  hasten  the  wear  of  the  brass, 
which  is  the  result  of  frequent  tightening.  The  slight- 
est play  in  the  bearings  of  the  engine-shaft  as  well  as 
in  the  bearings  of  connecting-rods  increases  the  sound 
that  engines  naturally  produce. 

Governor. — The  governor  should  receive  careful  at- 
tention so  far  as  its  cleanliness  is  concerned;  for  if  its 
operation  is  not  easy  it  is  apt  to  become  "  lazy  "  and 
to  lose  its  sensitiveness.  If  the  governor  be  of  the  ball 
type,  or  of  the  conical  pendulum  type  operated  by 
centrifugal  force,  it  is  well  to  lubricate  each  joint  with- 
out excess  of  oil.  In  order  to  prevent  the  accumula- 
tion and  the  solidification  of  oil,  the  governor  should 
be  lubricated  from  time  to  time  with  petroleum.  If 
the  governor  is  actuated  by  inertia,  which  is  the  case 


124    GAS-ENGINES    AND    PRODUCERS 

in  most  engines  of  the  hit-and-miss  variety,  it  needs 
less  care;  still,  it  is  advisable  to  keep  the  contact  at 
which  the  thrust  takes  place  well  oiled. 

The  operation  of  any  of  these  governors  is  usually 
controlled  by  the  tension  of  a  spring,  or  by  a  counter- 
weight. In  order  to  increase  the  speed  of  the  engine, 
or  in  other  words,  to  increase  the  number  of  admissions 
of  gas  in  a  given  time,  all  that  is  usually  necessary  is 
to  tighten  up  the  spring,  or  to  change  the  position  of 
the  counterweight.  It  should  be  possible  to  effect 
this  adjustment  while  the  engine  is  running  in  such  a 
manner  that  the  speed  can  be  easily  changed. 

Joints. — In  most  well-built  engines  the  caps  of  the 
valve-chests  and  other  removable  parts  are  secured 
"  metal  on  metal  "  without  interposing  special  joints. 
In  other  words,  the  surfaces  are  themselves  sufficiently 
cohesive  to  insure  perfect  tightness.  In  engines  which 
are  not  of  this  class,  asbestos  joints  are  very  frequently 
employed,  particularly  at  the  exhaust-valve  cap  and 
the  suction-valve. 

In  some  engines,  where  for  any  reason  it  is  necessary 
frequently  to  detach  the  caps, certain  precautions  should 
be  taken  to  protect  the  joints  so  that  they  may  not  be 
exposed  to  deterioration  whenever  they  are  removed. 
For  this  purpose,  they  are  first  immersed  in  water  in 
order  to  be  softened,  then  dried  and  washed  with  olive 
or  linseed  oil  on  the  side  upon  which  they  rest  in  the 
engine.  On  the  cap  side  they  are  dusted  with  talcum 
or  with  graphite.  Treated  in  this  manner,  the  joint 
will  adhere  on  one  side  and  will  be  easily  released  on 


TEMPERATURE    OF   THE   WATER      125 

0 

the  other.  Joints  that  are  liable  to  come  in  contact 
with  the  gases  in  the  explosion-chamber  should  be  free 
from  all  projections  toward  the  interior  of  the  cylin- 
der; for  during  compression  these  uncooled  projections 
may  become  incandescent  and  may  thus  cause  prema- 
ture ignition.  As  a  general  rule  when  the  cap  is 
placed  in  position  the  joint  should  be  retightened  after 
a  certain  time,  when  the  surfaces  have  become  suffi- 
ciently heated.  In  order  to  tighten  the  joints  the  bolts 
and  nuts  should  not  be  oiled;  otherwise  the  removal  of 
the  cap  becomes  difficult. 

Water  Circulation. — In  a  previous  chapter,  the  im- 
portance of  the  water  circulation  and  the  necessity  of 
keeping  the  cylinder-jacket  hot,  have  been  sufficiently 
dwelt  upon.  As  the  cylinder  tends  to  become  hotter 
with  an  increase  in  the  load,  because  of  the  greater  fre- 
quency of  explosions,  it  is  advisable  to  regulate  the 
flow  of  the  water  in  order  to  prevent  its  becoming  more 
than  sufficient  in  quantity  when  the  engine  is  lightly 
loaded;  for  under  these  conditions  the  cylinder  will  be 
cold  and  the  explosive  mixture  will  be  badly  utilized. 
A  suitable  temperature  of  140  to  158  degrees  F.  is 
easily  maintained  by  adjusting  the  circulation  of  the 
water.  This  can  be  accomplished  by  providing  the 
water-inlet  pipe  leading  to  the  cylinder  with  a  cock 
which  can  be  opened  more  or  less,  as  may  be  necessary. 
The  temperature  of  140  to  158  degrees  F.  which  has 
been  mentioned  may,  at  first  blush,  seem  rather  high, 
because  it  would  be  impossible  to  keep  the  hand  on  the 
outlet-pipe.  The  cylinder,  however,  will  not  become 


126    GAS-ENGINES    AND    PRODUCERS 

overheated  so  long  as  it  is  possible  to  hold  the  hand 
beneath  the  jacket  near  the  water-inlet.  This  relates 
only  to  engines  having  a  compression  of  50  to  100  Ibs. 
per  square  inch.  For  engines  of  higher  compression, 
a  lower  running  temperature  will  be  safer.  On  this 
matter  the  instructions  of  the  engine  maker  should  be 
carried  out. 

Adjustment. — Gas-engines,  at  least  those  which  are 
built  by  trustworthy  firms,  are  always  put  to  the  brake 
test  before  they  are  sent  from  the  shops,  and  are  ad- 
justed to  meet  the  requirements  of  maximum  efficiency. 
But  since  the  nature  and  quality  of  gas  necessarily 
vary  with  each  city,  it  is  evident  that  an  engine 
adjusted  to  develop  a  certain  horse-power  with  a  gas 
of  a  certain  richness,  may  not  fulfil  all  expectations 
if  it  is  fed  with  a  gas  less  rich,  less  pure,  hotter,  and 
the  like.  The  altitude  also  has  some  influence  on  the 
efficiency  of  the  engine.  As  it  increases,  the  density  of 
the  mixture  diminishes;  that  is  to  say,  for  the  same  vol- 
ume the  engine  is  using  a  smaller  amount.  From  this 
it  follows  that  a  gas-engine  ought  to  be  adjusted  as  a 
general  rule  on  the  spot  where  it  is  to  be  used. 

The  fulfilment  of  this  condition  is  particularly  im- 
portant in  the  case  of  explosion-engines,  because  an 
advancement  or  retardation  of  only  one-half  a  second 
in  igniting  the  explosive  mixture  will  cause  a  consid- 
erable loss  in  useful  work.  From  this  it  would  follow 
that  gas-engines  should  be  periodically  inspected  in 
order  that  they  may  operate  with  the  highest  efficiency 
and  economy.  As  in  the  case  of  steam-engines,  it  is 


TESTING    THE    ENGINE  127 

f 

advisable  to  take  indicator  records  which  afford  con- 
clusive evidence  of  the  perturbations  to  which  every 
engine  is  subject  after  having  run  for  some  time. 

Most  gas-engine  users  either  have  no  indicating  in- 
struments at  their  disposal  or  else  are  not  sufficiently 
versed  in  their  employment  and  the  interpretation  of 
their  records  to  study  perturbations  by  their  means. 
For  this  reason  the  advice  of  experts  should  be  sought, 
—men  who  understand  the  meaning  of  the  diagrams 
taken  and  who  are  able  by  their  means  to  effect  a  con- 
siderable saving  in  gas. 


CHAPTER   VIII 

HOW    TO    START    AN    ENGINE — PRELIMINARY    PRECAU- 
TIONS 

THE  first  step  which  is  taken  in  starting  an  engine 
driven  by  street-gas  is,  naturally,  the  opening  of  the 
meter-cock  and  the  valves  between  the  meter  and 
the  engine.  When  the  gas  has  reached  the  engine,  the 
rubber  bags  will  swell  up  and  the  anti-pulsator  dia- 
phragm will  be  forced  out.  The  drain-cock  of  the  gas- 
pipe  is  then  opened.  In  order  to  ascertain  whether 
the  flow  of  gas  is  pure,  a  match  is  applied  to  the  outlet 
of  the  cock.  The  flame  is  allowed  to  burn  until  it 
changes  from  its  original  blue  color  to  a  brilliant 
yellow. 

If  the  hot-tube  system  of  ignition  be  employed,  the 
Bunsen  burner  is  ignited,  care  being  taken  that  the 
flame  emerging  from  the  tube  is  blue  in  color.  If 
necessary  the  admission  of  air  to  the  burner  is  regu- 
lated by  the  usual  adjusting-sleeve.  A  white  or  smoky 
flame  indicates  an  insufficient  supply  of  air  to  the 
burner.  A  characteristic  sooty  odor  is  still  other  evi- 
dence of  the  same  fact.  Sometimes  a  white  flame  may 
be  produced  by  the  ignition  of  the  gas  at  the  opening 
of  the  adjusting-sleeve.  A  blue  or  greenish  flame  is 

that  which  has  the  highest  temperature  and  is  the  one 

128 


LIGHTING    THE    HOT   TUBE          129 

which  should,  therefore,  be  obtained.  About  five  or 
ten  minutes  are  required  to  heat  up  the  tube,  owing  to 
the  material  of  which  it  is  made.  When  the  proper 
temperature  has  been  attained  the  tube  becomes  a  daz- 
zling cherry  red  in  color.  While  the  tube  is  being 
heated  up,  it  is  well  to  determine  whether  the  engine 
is  properly  lubricated  and  all  the  cups  and  oil  reser- 
voirs are  duly  filled  up.  The  cotton  waste  of  the 
lubricators  should  be  properly  immersed,  and  the  drip 
lubricators  examined  to  determine  whether  they  are 
supplying  their  normal  quantity  of  oil. 

The  regulating-levers  of  the  valves  should  be  oper- 
ated in  order  to  ascertain  whether  the  valves  drop  upon 
their  seats  as  they  should.  The  stem  of  the  exhaust- 
valve  should  be  lubricated  with  a  few  drops  of  petro- 
leum. 

If  the  ignition  system  employed  be  of  the  electric 
type,  with  batteries  and  coils,  tests  should  be  made  to 
determine  whether  the  current  passes  at  the  proper 
time  on  completing  the  circuit  with  the  contact 
mounted  on  the  intermediary  shaft.  This  contact 
should  produce  the  characteristic  hum  caused  by  the 
operation  of  the  coil. 

If  a  magneto  be  used  in  connection  with  the  igni- 
tion apparatus,  its  inspection  need  not  be  undertaken 
whenever  the  engine  is  started,  because  it  is  not  so 
likely  to  be  deranged.  Still,  it  is  advisable,  as  in  the 
case  of  ignition  by  induction-coils,  to  set  in  position 
the  device  which  retards  the  production  of  the  spark. 
This  precaution  is  necessary  in  order  to  avoid  a  prema- 


i3o    GAS-ENGINES    AND    PRODUCERS 

ture  explosion,  liable  to  cause  a  sharp  backward  revo- 
lution of  the  fly-wheel. 

After  the  ignition  apparatus  and  the  lubricators  have 
been  thus  inspected,  the  engine  is  adjusted  with  the 
piston  at  the  starting  position,  which  is  generally  indi- 
cated by  a  mark  on  the  cam-shaft.  The  starting  posi- 
tion corresponds  with  the  explosion  cycle  and  is  gen- 
erally at  an  angle  of  40  to  60  degrees  formed  by  the 
crank  above  the  horizontal  and  toward  the  rear  of  the 
engine.  The  gas-cock  is  opened  to  the  proper  mark, 
usually  shown  on  a  small  dial.  If  there  be  no  mark, 
the  cock  is  slowly  opened  in  order  that  no  premature 
explosion  may  be  caused  by  an  excess  of  gas. 

The  steps  outlined  in  the  foregoing  are  those  which 
must  be  taken  with  all  motors.  Each  system,  how- 
ever, necessitates  peculiar  precautions,  which  are 
usually  given  in  detailed  directions  furnished  by  the 
builder. 

As  a  general  rule  the  engines  are  provided  on  their 
intermediary  shafts  with  a  "  relief  "  or  "  half-com- 
pression "  cam.  By  means  of  this  cam  the  fly-wrheel 
can  be  turned  several  times  without  the  necessity  of 
overcoming  the  resistance  due  to  complete  compres- 
sion. Care  should  be  taken,  however,  not  to  release 
the  cam  until  the  engine  has  reached  a  speed  sufficient 
to  overcome  this  resistance. 

Engines  of  considerable  size  are  commonly  provided 
with  an  automatic  starting  appliance.  In  order  to 
manipulate  the  parts  of  which  this  appliance  is  com- 
posed, the  directions  furnished  by  the  manufacturer 


PRELIMINARY   PRECAUTIONS       i?i 

9 

must  be  followed.  Particularly  is  this  true  of  auto- 
matic starters  comprising  a  hand-pump  by  means  of 
which  an  explosive  mixture  is  compressed, — true  be- 
cause in  the  interests  of  safety  great  care  must  be  taken. 

The  tightness  and  free  operation  of  the  valves  or 
clacks  which  are  intended  to  prevent  back  firing 
toward  the  pump  should  be  made  the  subject  of  care- 
ful investigation.  Otherwise,  the  piston  of  the  pump 
is  likely  to  receive  a  sudden  shock  when  back  firing  oc- 
curs. 

When  the  engine  has  been  idle  for  several  days,  it 
is  advisable,  before  starting,  to  give  it  several  turns 
(without  gas)  in  order  to  be  sure  that  all  its  parts 
operate  normally.  The  same  precaution  should  be 
taken  in  starting  an  engine,  if  a  first  attempt  has  failed, 
in  order  to  evacuate  imperfect  mixtures  that  may  be 
left  in  the  cylinder.  Before  this  test  is  made,  the  gas- 
cock  should,  of  course,  be  closed  in  order  to  prevent 
an  untimely  explosion.  It  is  advisable  in  starting  an 
engine  not  to  bend  the  body  over  the  ignition-tube, 
because  the  tube  is  likely  to  break  and  to  scatter  dan- 
gerous fragments. 

Under  no  condition  whatever  should  the  fly-wheel 
be  turned  by  placing  the  foot  upon  the  spokes.  All 
that  should  be  done  is  to  set  it  in  motion  by  applying 
the  hand  to  the  rim. 

Care  During  Operation. — When  the  engine  has  ac- 
quired its  normal  speed,  the  governor  should  be  looked 
after  in  order  that  its  free  operation  may  be  assured 
and  that  all  possibility  of  racing  may  be  prevented. 


1 32    GAS-ENGINES    AND    PRODUCERS 

After  the  engine  has  been  running  normally  for  a  time, 
the  cocks  of  the  water  circulation  system  should  be 
manipulated  in  order  to  adjust  the  supply  of  water  to 
the  work  performed  by  the  engine.  In  other  words 
the  cylinder  should  be  kept  hot,  but  not  burning,  as 
previously  explained  in  the  paragraph  in  which  the 
water-jacket  is  discussed.  The  maintenance  of  a  suit- 
able temperature  is  extremely  important  so  far  as 
economy  is  concerned.  All  the  bearings  should  be  in- 
spected in  order  that  hot  boxes  may  be  obviated. 

Stopping  the  Engine.— The  steps  to  be  taken  in 
stopping  the  engine  are  the  following: 

1.  Stopping  the  various  machines  driven  by  the  en- 
gine,— a  practice  which  is  followed  in  the  case  of  all 
motors ; 

2.  Throwing  out  the  driving-pulley  of  the  engine 
itself,  if  there  be  one; 

3.  Closing  the  cock  between  the  meter  and  the  gas- 
bags in  order  to  prevent  the  escape  of  gas  and  the  use- 
less stretching  of  the  rubber  of  the  bags  or  of  the  anti- 
pulsating  devices; 

4.  Actuating  the  half-compression  or  relief  cam  as 
the  motor  slows  down,  in  order  to  prevent  the  recoil 
due  to  the  compression; 

5.  Closing  the  gas-admission  cock; 

6.  Shutting  off  the  supply  of  oil  of  free  flowing 
lubricators,  and  lifting  out  the  cotton  from  the  others. 

If  the  engine  be  used  to  drive  a  dynamo,  particularly 
a  dynamo  provided  with  metal  brushes,  the  precaution 
should  be  taken  of  lifting  the  brushes  before  the  en- 


HOW    TO    STOP    AN    ENGINE        133 

0 

gine  is  stopped  in  order  to  prevent  their  injury  by  a 
return  movement  of  the  armature-shaft; 

7.  Shutting  off  the  cooling-water  cock  if  running 
water  is  used. 

If  the  engine  is  exposed  to  great  cold,  the  freezing 
of  the  water  in  the  jacket  is  prevented  while  the  engine 
is  at  rest,  either  by  draining  the  jacket  entirely,  or  by 
arranging  a  gas  jet  or  a  burner  beneath  the  cylinder 
for  the  purpose  of  causing  the  water  to  circulate.  If 
such  a  burner  be  used  the  cocks  of  the  water  supply 
pipe  should,  of  course,  be  left  open. 


CHAPTER   IX 

PERTURBATIONS  IN  THE  OPERATION  OF  ENGINES  AND 
THEIR  REMEDY 

IN  this  chapter  will  be  discussed  certain  perturba- 
tions which  affect  the  operations  of  gas-engines  to  a 
more  marked  degree  than  lack  of  care  in  their  con- 
struction. In  previous  chapters  defects  in  operation 
due  to  various  causes  have  been  dwelt  upon,  such  as 
objectionable  methods  in  the  construction  of  an  engine, 
ill-advised  combination  of  parts,  defects  of  installation, 
and  the  like;  and  an  attempt  has  been  made  to  deter- 
mine in  each  case  the  conditions  which  must  be  ful- 
filled by  the  engine  in  order  to  secure  efficiency  and 
economy  at  a  normal  load. 

Difficulties  in  Starting. — The  preliminary  precau- 
tions to  be  taken  in  starting  an  engine  having  been  in- 
dicated, it  is  to  be  assumed  that  the  advice  given  has 
been  followed.  Nevertheless  various  causes  may  pre- 
vent the  starting  of  the  engine. 

Faulty  Compression. — Defective  compression,  as  a 
general  rule,  prevents  the  ignition  of  the  explosive 
mixture.'  Whether  or  not  the  compression  be  imper- 
fect can  be  ascertained  by  moving  the  piston  back  to 
the  period  corresponding  with  compression,  in  other 

words,  that  position  in  which  all  valves  are  closed. 

134 


FAULTY   COMPRESSION  135 

•  t 
If  no  resistance  be  encountered,  it  is  evident  that  the 

air  or  the  gaseous  mixture  is  escaping  from  the  cylin- 
der by  way  of  the  admission-valve,  the  exhaust-valve, 
or  the  piston.  The  valves,  ordinarily  seated  by  springs, 
may  remain  open  because  their  stems  have  become 
bound,  or  because  some  obstruction  has  dropped  in 
between  the  disk  and  the  seat.  In  a  worn-out  or  badly 
kept  engine  the  valves  are  likely  to  leak.  If  that  be 
the  case  grinding  is  the  only  remedy.  If  a  valve  be 
clogged,  which  becomes  sufficiently  evident  by  manip- 
ulating the  controlling  levers,  it  is  necessary  simply  to 
clean  the  stem  and  its  guides  in  order  to  remove  the 
caked  oil  which  accumulates  in  time.  If  the  engine  be 
new,  the  binding  of  the  valve-stems  is  often  caused  by 
insufficient  play  between  the  stems  and  their  guides. 
Should  this  prove  to  be  the  case,  the  defect  is  remedied 
by  rubbing  the  frictional  surface  of  the  stem  with  fine 
emery  paper  and  by  lubricating  it  with  cylinder-oil. 
The  exhaust-valve,  however,  should  be  lubricated  only 
with  petroleum. 

It  is  not  unlikely  that  the  exhaust-valve  may  leak 
for  two  other  reasons.  In  the  first  place,  the  tension  of 
the  spring  which  serves  to  return  the  valve  may  have 
lessened  and  may  be  insufficient  to  prevent  the  valve 
from  being  unseated  during  suction.  Again,  the  screw 
or  roller  serving  as  a  contact  between  the  lever  and  the 
valve-stem,  may  not  have  sufficient  play,  so  that  the 
lengthening  of  the  stem  on  account  of  its  expansion 
may  prevent  the  valve  from  falling  back  on  its  seat. 
The  first-mentioned  defect  is  remedied  by  renewing 


136    GAS-ENGINES    AND    PRODUCERS 

the  spring,  or  by  the  provision  of  an  additional  spring 
or  of  a  counterweight  in  order  to  prevent  the  stoppage 
of  the  motor.  The  second  defect  can  be  remedied  by 
regulating  the  contact. 

Leakage  past  the  piston  may  be  caused  by  the  break- 
ing of  one  or  more  rings,  by  wear  or  binding  of  the 
rings,  or  by  wear  or  binding  of  the  cylinder.  The 
whistling  caused  by  the  air  or  the  mixture  as  it  passes 
back  proves  the  existence  of  this  fault. 

Presence  of  Water  in  the  Cylinder. — It  may  some- 
times happen  that  water  may  find  its  way  into  the  cyl- 
inder with  the  gas  by  reason  of  the  bad  arrangement 
of  the  piping.  It  may  also  happen  that  water  may 
enter  the  cylinder  through  the  water-jacket  joint 
Again,  the  presence  of  water  in  the  cylinder  may  be 
due  to  condensation  of  the  steam  formed  by  the  chem- 
ical union  of  the  hydrogen  of  the  gas  and  the  oxygen  of 
the  air,  which  condensation  is  caused  by  the  cool  walls 
of  the  cylinder.  The  water  may  sometimes  accumulate 
in  the  exhaust  pipe  and  box,  when  they  have  been  im- 
properly drained,  and  may  thus  return  to  the  cylinder. 
Whatever  may  be  its  cause,  however,  the  presence  of 
water  in  the  cylinder  impedes  the  starting  of  the  en- 
gine, because  the  gases  resulting  from  the  explosion  are 
almost  spontaneously  chilled,  thereby  diminishing  the 
working  pressure. 

If  electric  ignition  be  employed,  drops  of  water  may 
be  deposited  between  the  contacts,  thereby  causing 
short  circuits  which  prevent  the  passing  of  the  spark. 

If  there  be  no  drain-cock  on  the  cylinder,  the  dim*- 


IMPERFECT    IGNITION  137 

•  ' 

culty  of  starting  the  engine  can  be  overcome  only  by 
ceaseless  attempts  to  set  it  in  motion.  The  leaky  con- 
dition of  a  joint  as  well  as  the  presence  of  a  particle  of 
gravel  in  the  cylinder-casting,  through  which  the  water 
can  pass  from  the  jacket,  is  attested  by  the  bubbling  up 
of  gas  in  the  water-tank  at  the  opening  of  the  supply 
tube.  These  bubbles  are  caused  by  the  passage  of  the 
gas  through  the  jacket  after  the  explosion.  If  such 
bubbles  be  detected,  the  cylinder  should  be  renewed 
or  the  defect  remedied.  In  order  to  obviate  any  dan- 
ger, the  stop-cocks  of  the  water-jacket,  which  have 
already  been  described  in  a  previous  chapter,  should  be 
closed  while  the  engine  is  idle. 

Imperfect  Ignition. — The  difficulties  encountered  in 
starting  an  engine,  and  caused  by  imperfect  ignition, 
vary  in  their  nature  with  the  character  of  the  .igni- 
tion system  employed,  whether  that  system,  for  ex- 
ample, be  of  the  electric,  or  of  the  incandescent  or  hot 
tube  type.  Frequently  it  happens  that  in  starting  an 
engine  a  hot  tube  may  break.  If  the  tube  be  of  porce- 
lain the  accident  may  usually  be  traced  to  improper 
fitting  or  to  the  presence  of  water  in  the  cylinder.  If 
the  tube  be  of  metal,  its  breaking  is  caused  usually  by 
a  weakening  of  the  metal  through  long  use — an  acci- 
dent that  occurs  more  often  in  starting  the  engine  than 
in  normal  operation,  because  the  explosions  at  starting 
are  more  violent,  owing  to  the  tendency  of  the  supply- 
pipes  to  admit  an  excess  of  gas  at  the  beginning. 

A  misfire  arising  from  a  faulty  tube  in  starting  may 
be  caused  by  an  obstruction  or  by  leaks  at  the  joints  or 


138    GAS-ENGINES    AND    PRODUCERS 


in  the  body  of  the  tube  itself,  thereby  allowing  a  certain 
quantity  of  the  mixture  to  escape  before  ignition.  This 
defect  in  the  tube  is  usually  disclosed  by  a  characteris- 
tic whistling  sound. 

A  tube  may  leak  either  at  the  bottom  or  at  the  .top. 
In  the  first  case,  starting  is  very  difficult,  because  the 
part  of  the  mixture  compressed  toward  the  tube  will 
escape  through  the  opening  before  it  reaches  the  in- 
candescent zone.  In  the  second  case,  ignition  may  be 


FIG.  74.  FIG.  75. 

Ignition -tubes  provided  with  needle  valves  to  facilitate  starting. 

simply  retarded  to  so  marked  an  extent  that  a  sufficient 
motive  effect  cannot  be  produced.  An  example  of  this 
retardation,  artificially  produced  to  facilitate  the  start- 
ing and  to  obviate  premature  explosions,  is  found  in  a 
system  of  ignition-tubes  provided  with  a  small  cock 
or  variable  valve  (Figs.  74  and  75). 

The  mere  enumeration  of  defects  caused  by  leakage 
is  sufficient  to  indicate  the  remedy  to  be  adopted.  It 
may  be  well  to  recall  in  this  connection  the  important 
part  played  by  the  ignition-valve.  If  it  be  leaky,  or  if 


IGNITION    BY    BATTERY  139 

• 

its  free  operation  be  impeded,  starting  will  always  be 
difficult. 

Electric  Ignition  by  Battery  or  Magneto. — If  the 
electric  ignition  apparatus,  whatever  may  be  the 
method  by  which  the  spark  is  produced,  be  imper- 
fect in  operation,  the  first  step  to  be  taken  is  to  ascertain 
whether  the  spark  is  produced  at  the  proper  time,  in 
other  words,  slightly  after  the  dead  center  in  the  par- 
ticular position  given  to  the  admission  device  at  start- 
ing. If  a  coil  and  a  battery  be  employed,  it  is  advis- 
able to  remove  the  plug  and  to  place  it  with  its  arma- 
ture upon  a  well-polished  metal  surface  to  produce  an 
electrical  contact,  preventing,  however,  the  contact  of 
the  binding  post  with  this  metallic  surface.  The  same 
method  of  inspection  is  adopted  with  the  make-and- 
break  apparatus  of  an  electric  magneto.  In  both  cases 
it  should  be  ascertained  whether  or  not  there  is  any 
short-circuiting.  The  contacts  should  be  cleaned  w7ith 
a  little  benzine  if  they  are  covered  with  oil  or  caked 
grease. 

If  no  spark  is  produced  at  the  plug  or  at  the  make- 
and-break  device  it  may  be  inferred  that  the  wires  are 
broken  or  that  the  generating  apparatus  is  out  of  order. 
A  careful  examination  will  indicate  what  measures  are 
to  be  taken  to  cure  the  defects. 

Premature  Ignition. — It  has  several  times  been 
stated  that  the  moment  of  ignition  of  the  gaseous  mix- 
ture has  a  pronounced  influence  on  the  operation  of 
gas-engines  and  upon  their  economy. 

Premature  ignition  takes  place  when  there  is  a  vio- 


140    GAS-ENGINES    AND    PRODUCERS 

lent  shock  at  the  moment  when  the  piston  leaps  from 
the  rear  dead  center  to  the  end  of  the  compression 
stroke.  The  violent  effects  produced  are  all  the  more 
harmful  because  they  tend  to  overheat  the  interior  of 
the  engine  and  thereby  to  increase  in  intensity. 

Premature  ignition  may  be  due  to  several  causes. 
If  a  valveless  hot  tube  be  employed  it  may  happen 
that  the  incandescent  zone  is  too  near  the  base.  If 
the  tube  be  provided  with  a  valve,  it  very  frequently 
happens  that  the  valve  leaks  or  that  it  opens  too  soon. 
In  the  case  of  electric  ignition,  the  circuit  may  be 
completed  before  the  proper  time,  because  of  faulty 
regulation.  The  suggestions  made  in  the  preceding 
chapters  indicate  the  method  of  remedying  these 
defects. 

Faulty  ignition  may  have  its  origin  not  only  in  the 
method  of  ignition  employed,  but  also  in  excessive  heat- 
ing of  the  internal  parts  of  the  engine,  caused  by  con- 
tinual overloading  or  by  inadequate  circulation  of 
water. 

Passing  to  those  cases  of  premature  ignition  of  a 
special  nature  which  are  not  due  to  any  functional  de- 
fect in  the  engine,  but  which  are  purely  accidental  in 
origin,  such  as  the  uncleanliness  of  the  parts  within  the 
cylinder  or  the  presence  of  some  projecting  part  which 
becomes  heated  to  incandescence  during  compression, 
it  should  first  be  stated  that  these  ignitions,  usually 
termed  spontaneous,  often  occur  well  in  advance  of  the 
end  of  the  compression  stroke.  They  are  characterized 
by  a  more  marked  shock  than  that  caused  by  ordinary 


UNTIMELY    DETONATIONS          141 

• 

premature  ignition  and  usually  result  in  bringing  the 
engine  to  a  complete  stop  in  a  very  short  time.  These 
spontaneous  explosions  counteract  to  such  an  extent 
the  impulse  of  the  compression  period,  during  which 
the  piston  is  moving  back,  that  they  have  a  tendency 
to  reverse  the  direction  in  which  the  engine  is  running. 
In  such  cases  a  careful  inspection  and  a  scrupulous 
cleaning  of  the  cylinder  and  of  the  piston  should  be 
undertaken. 

The  bottom  of  the  piston  is  particularly  likely  to  re- 
tain grease  which  has  become  caked,  and  which  is 
likely  to  become  heated  to  incandescence  and  sponta- 
neously to  ignite  the  explosive  mixture. 

Untimely  Detonations. — The  sound  produced  by 
the  explosions  of  a  normally  operating  engine  can 
hardly  be  heard  in  the  engine-room.  Untimely  detona- 
tions are  produced  either  at  the  exhaust,  or  in  the  suc- 
tion apparatus,  near  the  engine  itself.  These  detona- 
tions are  noisier  than  they  are  dangerous;  still,  they 
afford  evidence  of  some  fault  in  the  operation  which 
should  be  remedied. 

Detonations  produced  at  the  exhaust  are  caused  by 
the  burning  of  a  charge  of  the  explosive  mixture  in  the 
exhaust-pipe,  which  charge,  for  some  reason,  has  not 
been  ignited  in  the  cylinder,  and  has  been  driven  into 
the  exhaust-pipe,  where  it  catches  fire  on  coming  into 
contact  with  the  incandescent  gases  discharged  from 
the  cylinder  after  the  following  explosion. 

Detonations  produced  in  the  suction  apparatus  of 
the  engine,  which  apparatus  is  either  arranged  in  the 


142    GAS-ENGINES    AND    PRODUCERS 

base  itself  or  in  a  separate  chest,  are  often  noisier  than 
the  foregoing.  They  are  caused  by  the  accidental  back- 
ward flowing  of  the  explosive  mixture,  and  by  its  igni- 
tion outside  of  the  cylinder.  The  accident  may  be 
traced  to  three  causes : 

1.  The  suction-valve  of  the  mixture  may  not  be  tight 
and  may  leak  during  the  period  of  compression,  allow- 
ing a  certain  quantity  of  the  mixture  to  pass  into  the 
suction-chest  or  into  the  frame.     When  the  explosion 
takes  place  in  the  cylinder  that  part  of  the  mixture 
which  has  passed  back  is  ignited,  as  we  have  just  seen, 
thereby  producing  a  very  loud  deflagration.    The  ob- 
vious remedy  consists  in  making  the  suction-valve  tight 
by  carefully  grinding  it. 

2.  It  may  happen  that  at  the  end  of  the  exhaust 
stroke  incandescent  particles  may /remain  in  the  cylin- 
der, which  particles  may  consist  of  caked  oil  or  may 
be  retained  by  poorly  cooled  projections.    The  result  is 
that  the  mixture  is  prematurely  ignited  during  the  suc- 
tion period. 

3.  The  engine  is  so  regulated,  particularly  in  the 
case  of  English-built  engines,  as  to  effect  what  is  tech- 
nically called  "  scavenging  "  the  products  of  combus- 
tion.    In  order  to  obtain  this  result,  the  mixture-valve 
is  opened  before  the  end  of  the  exhaust  stroke  of  the 
piston  and  the  closing  of  the  exhaust-valve.    Owing  to 
the  inertia  and  the  speed  acquired  by  the  products  of 
combustion  shot  into  the  exhaust-pipe  after  explosion, 
a  lowering  of  the  pressure  is  produced  in  the  cylinder 
toward  the  end  of  the  stroke,  causing  the  entrance  of 


RETARDED    EXPLOSIONS 


'43 


air  by  the  open  admission-valve  and  consequently 
effecting  the  scavenging  of  the  burnt  gases,  part  of 
which  would  otherwise  remain  in  the  cylinder.  It  is 
evident  that  if  a  charge  of  the  mixture  has  not  been 
normally  exploded,  either  because  its  constituents  have 
not  been  mingled  in  the  proper  proportion,  or  because 
the  ignition  apparatus  has  missed  fire,  this  charge  at  the 
moment  of  exhausting  will  pass  out  of  the  cylinder 
without  any  acquired  speed,  and  will  flow  back  in  part 
at  the  end  of  the  exhaust  stroke  past  the  prematurely 
opened  admission-valve,  thereby  lodging  in  the  air  suc- 
tion apparatus.  Despite  the  suction  which  takes  place 
immediately  following  the  re-entrance  of  the  gas  int.o 
the  cylinder,  a  certain  quantity  of  the  mixture  is  still 
confined  in  the  suction-pipe  and  its  branches,  where  it 
will  catch  fire  at  the  end  of  the  exhaust  stroke  after  the 
opening  of  the  mixture-valve. 

In  order  to  avoid  these  detonations  it  is  necessary 
simply  to  see  to  it  that  the  mixture  is  regularly  ignited. 
This  is  accomplished  by  mixing  the  gas  and  air  in 
proper  proportions  or  by  correcting  the  ignition  time. 

Retarded  Explosions. — Retarded  explosions  consid- 
erably reduce  the  power  which  an  engine  should  nor- 
mally yield,  and  sensibly  increase  the  consumption. 
They  are  due  to  three  chief  causes:  (i),  faulty  igni- 
tion; (2),  the  poor  quality  of  the  mixture;  (3),  com- 
pression losses.  The  existence  of  the  defect  cannot  be 
ascertained  with  any  certainty  without  the  use  of  an 
indicator  or  of  some  registering  device  which  gives 
graphic  records.  Nevertheless,  it  is  possible  in  some 


144    GAS-ENGINES    AND    PRODUCERS 

degree  to  detect  retarded  explosions,  simply  by  ob- 
serving whether  there  is  a  diminution  in  the  power  or 
an  excessive  consumption,  despite  the  perfect  operation 
and  good  condition  of  all  the  engine  parts. 

In  order  to  remedy  the  defect  it  should  be  ascer- 
tained if  the  compression  is  good,  if  the  supply  of  gas 
is  normal,  and  if  the  conditions  under  which  the  mix- 
ture of  air  and  gas  is  produced  have  not  been  changed. 
Lastly,  the  ignition  apparatus  is  gradually  adjusted  to 
accelerate  its  operation  until  a  point  is  reached  when, 
after  explosion,  shocks  are  produced  which  indicate  an 
excessive  advance.  The  ignition  apparatus  is  then  ad- 
justed to  a  point  slightly  ahead  of  the  corresponding 
position.  Recalling  the  descriptions  already  given  of 
the  various  systems  of  ignition,  the  manner  of  regulat- 
ing the  moment  of  ignition  in  each  case  may  be  sum- 
marized as  follows : 

1.  For    the    valveless    incandescent    tube,    provided 
with  a  burner  the  position  of  which  can  be  varied, 
ignition  can  be  accelerated  by  bringing  the  burner 
nearer  to  the  base.     Retardation  is  effected  by  moving 
the  burner  away  from  the  base. 

2.  In  the  case  of  the  incandescent  tube  of  the  fixed 
burner  type,  the  moment  of  ignition  will  depend  upon 
the  length  of  the  tube.    The  retardation  will  be  greater 
as  the  tube  is  shorter,  and  vice  versa. 

3.  If  the  tube  be  provided  with  an  ignition-valve, 
the   time   of   ignition   having  been    regulated   by   the 
maker,  regulation  need  not  be  undertaken  except  if  the 
valve-stem  be  worn  or  the  controlling-cam  be  distorted. 


RETARDED    EXPLOSIONS  145 

0 

If  these  defects  should  be  noted,  the  imperfect  parts 
should  be  repaired  or  renewed. 

4.  In  electric  igniters  the  controlling  apparatus 
is  generally  provided  with  a  regulating  device  which 
may  be  manipulated  during  the  operation  of  the  motor. 
If  the  manual  adjustment  of  the  regulating  apparatus 
be  unproductive  of  satisfactory  results,  it  is  advisable 
to  ascertain  whether  the  spark  is  being  produced  nor- 
mally. Before  the  engine  has  come  to  a  stop,  one  of 
the  valve-casings  is  raised,  and  through  the  opening 
thus  produced  it  is  easily  seen  whether  the  spark  is  of 
sufficient  strength,  the  engine  in  the  meanwhile  being 
turned  by  hand.  Care  should  always  be  taken  to  purge 
the  cylinder  of  the  gas  that  it  may  contain,  in  order  to 
prevent  dangerous  explosions.  If  the  spark  should 
prove  to  be  too  feeble,  or  if  there  be  no  spark  at  all,  de- 
spite the  fact  that  every  part  of  the  mechanism  is  prop- 
erly adjusted,  it  may  be  inferred  that  the  fault  lies  with 
the  current  and  is  caused  by 

1.  Imperfect  contact  with   the  binding-posts,  with 
the    conducting   wire,    or   with    the    contact-breaking 
members; 

2.  A  short  circuit  in  one  of  the  dismembered  pieces; 

3.  The  presence  of  a  layer  of  oil  or  of  caked  grease 
forming  an  insulator,  injurious  to  induction,  between 
the  armature  and  the  magnets; 

4.  A  deposit  of  oil  or  moisture  on  the  contact-break- 
ing parts; 

5.  The  exhaustion  of  the  magnets,  which,  however, 
occurs  only  after  several  years  of  use,  except  when  the 


146    GAS-ENGINES    AND    PRODUCERS 

magneto  has  been  subjected  for  a  long  time  to  a  high 
temperature. 

The  mere  discovery  of  any  of  these  defects  suffi- 
ciently indicates  the  means  to  be  adopted  in  remedying 
them. 

Lost  Motion  in  Moving  Parts.— Lost  motion  of 
the  moving  parts  is  due  to  structural  errors.  Its  cause 
is  to  be  found  in  the  insufficient  size  of  the  frictional 
bearing  surfaces,  and  improper  proportioning  of  shafts, 
pins,  and  the  like.  The  result  is  a  premature  wear 
which  cannot  be  remedied.  Imperfect  adjustment, 
lack  of  care,  and  bad  lubrication,  may  also  hasten  the 
wear  of  certain  parts.  This  wear  is  manifested  in 
shocks,  occurring  during  the  operation  of  the  engine,— 
shocks  which  are  particularly  noticeable  at  the  moment 
of  explosion. 

Besides  the  inconveniences  mentioned,  wearing  of  the 
gears  and  of  the  moving  parts  leads  to  derangement  of 
the  power-transmitting  members. 

So  far  as  the  admission  and  exhaust  valves  are  con- 
cerned, the  wearing  of  the  cams,  rollers,  and  lever- 
pivots  is  evidenced  by  a  retardation  in  the  opening  of 
these  valves  and  an  acceleration  in  their  closing. 

The  ignition,  whatever  may  be  the  system  employed, 
is  affected  by  lost  motion  and  is  retarded.  The  engine 
appreciably  loses  in  power,  and  its  consumption  be- 
comes excessive. 

Overheated  Bearings. — Apart  from  the  imperfect 
adjustment  of  a  member,  it  may  happen  that  the  bush- 
ings of  the  main  bearings  of  the  ends  of  the  connecting- 


OVERHEATED    BEARINGS  147 

rod,  and  of  the  piston-pivot,  may  become  heated  be- 
cause of  excessive  play,  or  of  too  much  tightening,  or  of 
a  lack  of  oil,  or  of  the  employment  of  oil  of  bad  quality. 
The  overheating  may  lead  to  the  binding  of  frictional 
surfaces  and  even  to  the  fusion  of  bushings  if  they  be 
lined  with  anti-friction  metal.  In  order  to  avoid  the 
overheating  of  parts,  it  is  advisable,  while  the  engine 
is  running,  to  touch  them  from  time  to  time  with  the 
back  of  the  hand.  As  soon  as  the  slightest  overheating 
is  felt,  the  temperature  may  be  lowered  often  by  liberal 
oiling.  If  this  be  inadequate  and  if  for  special  reasons 
it  is  impossible  to  stop  the  engine,  the  overheated  part 
may  be  cooled  by  spraying  it  with  soapy  water. 

If  the  overheating  has  not  been  detected  or  reduced 
in  time,  a  characteristic  odor  of  burnt  oil  will  -be  per- 
ceived, accompanied  by  smoke.  The  part  overheated 
will  then  have  attained  a  temperature  so  high  that  it 
cannot  be  touched  with  the  hand.  Should  this  occur, 
it  is  inadvisable  to  employ  oil,  because  it  would  im- 
mediately burn  up  and  would  Only  aggravate  the  con- 
ditions. Cotton  waste  should  be  carefully  applied  to 
the  overheated  member,  and  gradual  spraying  with 
soapy  water  begun. 

In  special  cases  where  the  lubricating  openings  or 
channels  are  not  likely  to  be  obstructed,  a  little  flowers 
of  sulphur  may  be  added  to  the-  oil,  if  this  be  very  fluid. 
Castor  oil  may  also  be  successfully  employed. 

If  the  binding  of  the  rubbing  surfaces  should  pre- 
vent the  reduction  of  the  overheated  member's  tempera- 
ture, the  engine  must  necessarily  be  stopped,  and  the 


148    GAS-ENGINES    AND    PRODUCERS 

parts  affected  detached.  All  causes  of  binding  are  re- 
moved by  means  of  a  steel  scraper.  The  surfaces  of  the 
bushings  and  of  the  shaft  which  they  receive  are 
smoothed  with  a  soft  file  and  then  polished  with  fine 
emery  paper.  Before  the  parts  are  replaced,  the  pre- 
caution of  ascertaining  whether  they  touch  at  all  points 
should  be  taken.  Careful  inspection  and  copious  lubri- 
cation should,  of  course,  be  undertaken  when  the  en- 
gine is  again  started. 

Overheating  of  the  Cylinder.— The  overheating  of 
the  cylinder  may  be  due  to  a  complete  lack  of  water 
in  the  jacket  or  to  an  accidental  diminution  in  the  quan- 
tity of  water  supplied.  If  this  discovery  is  made  too 
late,  and  if  the  cylinder  has  reached  a  very  high  tem- 
perature, the  circulation  of  the  water  should  not  be 
suddenly  re-established,  because  of  the  liability  of 
breaking  the  casting.  It  is  best  to  stop  the  engine  and 
to  restore  the  parts  to  their  normal  condition. 

It  is  well  to  recall  at  this  point  that  if  the  calcareous 
incrustation  of  the  water-jacket  or  the  branch  pipes 
should  hinder  the  free  circulation  of  water,  cleaning  is, 
of  course,  necessary.  The  jacket  may  be  washed  sev- 
eral times  with  a  twenty  per  cent,  solution  of  hydro- 
chloric acid.  After  this  treatment  the  jacket  should,  of 
course,  be  rinsed  with  fresh  water  before  the  piping  of 
the  water-circulating  apparatus  is  again  connected. 

Overheating  of  the  Piston. — If  the  overheating  of 
the  piston  is  not  due  to  faulty  adjustment,  it  may  be 
caused  by  lack  of  oil  or  to  the  employment  of  a  lubri- 
cant not  suitable  for  the  purpose.  In  a  previous  chap- 


OVERHEATED    PISTON 


149 


ter  the  importance  of  using  a  special  oil  for  cylinder 
lubrication  has  been  insisted  upon.  The  overheating 
of  the  piston  can  also  result  from  that  of  the  piston-pin. 
Should  this  be  the  case  it  is  advisable  to  stop  the  engine, 
to  ascertain  the  condition  and  the  degree  of  lubrica- 
tion of  this  member  and  its  bearing.  Overheating  of 
the  piston  is  manifested  by  an  increase  of  the  tempera- 
ture of  the  cylinder  at  the  forward  end.  If  this  over- 
heating be  not  checked,  binding  of  the  piston  in  the 
cylinder  is  likely  to  result. 

Smoke  Arising  from  the  Cylinder.— This  is  gen- 
erally a  sign  either  of  overheating,  which  causes  the 
oil  to  evaporate,  or  of  an  abnormal  passage  of  gas, 
caused  by  the  explosion.  Abnormal  passage  of  gas 
may  result  from  wear  or  from  distortion  of  the  cylin- 
der, or  from  wear  or  breakage  of  the  piston-rings.  The 
result  is  always  the  overheating  of  the  cylinder  and  a 
reduction  in  compression  and  power. 

If  the  engine  is  well  kept  and  shows  no  sign  of  wear, 
leakage  may  be  caused  simply  by  the  fouling  of  the 
piston-rings,  which  then  adhere  in  their  grooves  and 
have  but  insufficient  play.  This  defect  is  obviated  by 
cleaning  the  rings  in  the  manner  explained  in  Chapter 
VII. 

Lubrication  is  faulty  when  the  quantity  of  lubricant 
supplied  is  either  insufficient  or  too  abundant,  or  when 
the  oils  employed  are  of  bad  quality.  It  has  already 
been  shown  that  insufficient  lubrication  and  the  utiliza- 
tion of  bad  oils  leads  to  the  overheating  of  the  moving 
parts. 


150    GAS-ENGINES    AND    PRODUCERS 

Insufficient  lubrication  may  be  caused  by  imperfect 
operation  of  the  lubricators,  or,  particularly  during 
cold  weather,  by  too  great  a  viscosity  or  congelation  of 
the  oil.  If  a  lubricator  be  imperfect  in  its  operation, 
the  condition  of  its  regulating  mechanism  should  be  as- 
certained, if  it  has  any,  and  an  examination  made  to  dis- 
cover any  obstruction  in  the  oil-ducts.  Such  obstruc- 
tions are  very  likely  to  occur  in  new  devices  which  have 
been  packed  in  cotton  waste  or  excelsior,  with  the  re- 
sult that  the  particles  of  the  packing  material  often  find 
their  way  into  openings. 

An  oil  may  be  bad  in  quality  because  of  its  very 
nature,  or  because  of  the  presence  of  foreign  bodies. 
In  either  case  an  oil  of  better  quality  should  be  sub- 
stituted. 

The  freezing  of  oil  by  intense  cold  may  be  retarded 
by  the  addition  of  ordinary  petroleum  to  the  amount  of 

10  to  20  per  cent. 

An  excess  of  oil  in  the  bearings  results  simply  in 
an  unnecessary  waste  of  lubricant,  and  the  splashing 
of  oil  on  the  engine  and  about  the  room.  If  too  much 

011  be  used  in  the  cylinder,  grave  consequences  may  be 
the  result;  for  a  certain  quantity  of  the  oil  is  likely  to 
accumulate  within  the  cylinder,  where  it  burns  and 
forms  a  caky  mass  that  may  be  heated  to  incandescence 
and  prematurely  ignite   the  explosive  mixture.      Es- 
pecially in  producer-gas  engines  is  an  excess  of  cylin- 
der-lubricant likely  to  cause  such  accidents.     Indeed, 
the  temperature  of  explosion  not  being  as  high  as  in 
street-gas  engines,  the  excess  oil  cannot  be  so  readily 


SUDDEN    STOPS  ici 

• 

removed  with  certainty  by  evaporation  or  combustion. 
On  the  other  hand,  the  compression  of  the  mixture 
being  generally  higher,  premature  ignition  is  very 
likely  to  occur. 

Back  Pressure  to  the  Exhaust. — How  the  pipes  and 
chests  for  the  exhaust  should  be  arranged  in  order  not 
to  exert  a  harmful  influence  on  the  motor  has  already 
been  explained.  Even  if  the  directions  given  have  been 
followed,  however,  the  exhaust  may  not  operate  prop- 
erly from  accidental  causes.  Among  these  causes  may 
be  mentioned  obstructions  in  the  form  of  foreign  bod- 
ies, such  as  particles  of  rust,  which  drop  from  the  in- 
terior of  the  pipes  after  the  engine  has  been  running 
for  some  time  and  which,  accumulating  at  any  place  in 
the  pipe,  are  likely  to  clog  the  passage.  Furthermore, 
the  products  of  combustion  may  contain  atomized  cyl- 
inder oil  which  finds  its  way  into  the  exhaust-pipe. 
This  oil  condenses  on  the  walls  of  the  elbows  and  bends 
of  the  pipe  in  a  deposit  which,  as  it  carbonizes,  is  con- 
verted into  a  hard  cake  and  which  reduces  the  cross- 
section  of  the  passage,  thereby  constituting  a  true  ob- 
stacle to  the  free  exhaust  of  the  gases. 

These  various  defects  are  manifested  in  a  loss  in 
engine  power  as  well  as  in  an  abnormal  elevation  of 
the  temperature  of  the  parts  surrounding  the  exhaust 
opening. 

Sudden  Stops. — Sudden  stops  are  occasioned  by 
faulty  operation  of  the  engine,  and  by  imperfect  fuel 
supply.  Among  the  first  class  the  chief  causes  to  be 
mentioned  are  the  following: 


152    GAS-ENGINES    AND    PRODUCERS 

1.  Overheating,  which  has  already  been  discussed 
and  which  may  block  a  moving  part. 

2.  Defective"  ignition. 

3.  Binding  of  the  admission-valve  or  of  the  exhaust- 
valve,  preventing  respectively  suction  or  compression. 

4.  The  breaking  or  derangement  of  a  member  of  the 
distributing  mechanism. 

5.  A  weakening  of  the  exhaust-valve  spring,  so  that 
the  valve  is  opened  by  the  suction  of  fresh  quantities  of 
mixture. 

These  faults  are  due  to  carelessness  and  improper  in- 
spection of  the  engine. 

So  far  as  the  fuel  supply  of  the  engine  is  concerned, 
the  causes  of  stoppage  will  vary  if  street-gas  or  pro- 
ducer-gas be  employed.  In  the  former  case  the  diffi- 
culty may  be  occasioned  by  the  improper  operation  of 
the  meter,  by  the  formation  of  a  water-pocket  in  the 
piping,  by  the  binding  of  an  anti-pulsator  valve,  by  the 
derangement  of  a  pressure-regulator,  or  by  a  sudden 
change  in  the  gas  pressure  when  no  pressure-regulator 
is  employed.  If  producer-gas  be  used,  stoppages  may 
be  occasioned  by  a  sudden  change  in  the  quality,  quan- 
tity, or  temperature  of  the  gas.  These  defects  will  be 
examined  in  detail  in  the  chapter  on  Gas-Producers. 


CHAPTER  X 

PRODUCER-GAS   ENGINES 

THUS  far  only  street-gas  or  illuminating-gas  engines 
have  been  discussed.  If  the  engine  employed  be  small 
— 10  to  15  horse-power,  for  instance — street-gas  is  a 
fuel,  the  richness,  purity  and  facility  of  employment 
of  which  offsets  its  comparatively  high  cost.  But 
the  constantly  increasing  necessity  of  generating 
power  cheaply  has  led  to  the  employment  of  special 
gases  which  are  easily  and  cheaply  generated.  Such 
are  the  following: 

Blast-furnace  gases, 

Coke-oven  gases, 

Fuel-gas  proper, 

Mond  gas, 

Mixed  gas, 

Water-gas, 

Wood-gas. 

The  practical  advantages  resulting  from  the  utiliza- 
tion of  these  gases  in  generating  power  were  hardly 
known  until  within  the  last  few  years.  The  many  uses 
to  which  these  gases  have  been  applied  in  Europe  since 
1900  have  definitely  proved  the  industrial  value  of  pro- 
ducer-gas engines  in  general. 

The  steps  which  have  led  to  this  gradually  increasing 
use  of  producer-gas  have  been  learnedly  discussed  and 

commented  upon  in  the  instructive  works  and  publica- 

153 


154    GAS-ENGINES    AND    PRODUCERS 

tions  of  Aime  Witz,  Professor  in  the  Faculty  of 
Sciences  of  Lille,  in  those  of  Dugald  Clerk,  of  Lon- 
don, F.  Grover,  of  Leeds,  and  Otto  Giildner,  of  Mu- 
nich, and  in  those  of  the  American  authors,  Golding- 
ham,  Hiscox,  Hutton,  Parsell  and  Weed,  etc.  The 
new  tendencies  in  the  construction  of  large  engines  may 
be  regarded  as  an  interesting  verification  of  the  fore- 
casts of  these  men — forecasts  which  coincide  with  the 
opinion  long  held  by  the  author.  Aime  Witz  has 
always  been  an  advocate  of  high  pressures  and  of  in- 
creased piston  speed.  English  builders  who  made  ex- 
periments in  this  direction  conceded  the  beneficial  re- 
sults obtained;  but  while  they  increased  the  original 
pressure  of  28  to  43  pounds  per  square  inch  employed 
five  or  six  years  ago  to  the  pressure  of  85  to  100  pounds 
per  square  inch  nowadays  advocated,  the  Germans,  for 
the  most  part,  have  adopted,  at  least  in  producer-gas 
engines,  pressures  of  114  to  170  pounds  per  square 
inch  and  more. 

High  Compression. — In  actual  practice,  the  problem 
of  high  pressures  is  apparently  very  difficult  of  solu- 
tion, and  many  of  the  best  firms  still  seem  to  cling  to 
old  ideas.  The  reason  for  their  course  is,  perhaps,  to 
be  found  in  the  fact  that  certain  experiments  which  they 
made  in  raising  the  pressures  resulted  in  discouraging 
accidents.  The  explosion-chambers  became  over- 
heated; valves  were  distorted;  and  premature  ignition 
occurred.  Because  the  principle  underlying  high  pres- 
sures was  improperly  applied,  the  results  obtained  were 
poor. 


HIGH    COMPRESSION 


. 


High  pressures  cannot  be  used  with  impunity  in  cyl- 
inders not  especially  designed  for  their  employment; 
and  this  is  the  case  with  most  engines  of  the  older  type, 
among  which  may  be  included  most  engines  of  English, 
French,  and  particularly  of  American  construction. 
In  American  engines  notably,  the  explosion-chamber, 
the  cylinder  and  its  jacket,  are  generally  cast  in  one 
piece,  so  that  it  is  very  difficult  to  allow  for  the  free  ex- 
pansion of  certain  members  with  the  high  and  unequal 
temperatures  to  which  they  are  subjected  (Fig.  22). 

Some  builders  have  attempted  to  use  high  pressures 
without  concerning  themselves  in  the  least  with  a  modi- 
fication of  the  explosive  mixture.  The  result  has  been 
that,  owing  to  the  richness  of  the  mixture,  the  explosive 
pressure  was  increased  to  a  point  far  beyond  that  for 
which  the  parts  were  designed.  Sudden  starts  and  stops 
in  operation,  overheating  of  the  parts,  and  even  break- 
ing of  crank-shafts,  were  the  results.  The  engines  had 
gained  somewhat  in  power,  but  no  progress  had  been 
made  in  economy  of  consumption,  although  this  was 
the  very  purpose  of  increasing  the  compression. 

High  pressures  render  it  possible  to  employ  poor 
mixtures  and  still  insure  ignition.  A  quality  of  street- 
gas,  for  example,  which  yields  one  horse-power  per 
hour  with  17.5  cubic  feet  and  a  mixture  of  i  part  gas 
and  8  of  air  compressed  to  78  pounds  per  square  inch, 
will  give  the  same  power  as  14  cubic  feet  of  the  same 
gas  mixed  with  12  parts  of  air  and  compressed  to  171 
pounds  per  square  inch. 

"  Scavenging"  of  the  cylinder,  a  practice  which  en- 


156    GAS-ENGINES    AND    PRODUCERS 

gineers  of  modern  ideas  seem  to  consider  of  much  im- 
portance, is  better  effected  with  high  pressures,  for  the 
simple  reason  that  the  explosion-chamber,  at  the  end 
of  the  return  stroke,  contains  considerably  less  burnt 
gases  when  its  volume  is  smaller  in  proportion  to  that 
of  the  cylinder. 

In  impoverishing  the  mixture  to  meet  the  needs  of 
high  pressures,  the  explosive  power  is  not  increased  and 
in  practice  hardly  exceeds  365  to  427  pounds  per  square 


FIG.  76. — Method  of  cooling  the  cylinder-head. 

inch.  With  the  higher  pressures  thus  obtained  there 
is  consequently  no  reason  for  subjecting  the  moving 
parts  to  greater  forces. 

Cooling. — The  increase  in  temperature  of  the  cylin- 
der-head and  of  the  valves,  due  wholly  to  high  com- 
pression, is,  perfectly  counteracted  by  an  arrangement 
which  most  designers  seem  to  prefer,  and  which,  as 
shown  in  the  accompanying  diagram  (Fig.  76),  con-* 
sists  in  placing  the  mixture  and  exhaust-valves  in  a 
passage  forming  a  kind  of  antechamber  completely 


COOLING  157 

.  f 

surrounded  by  water.  The  immediate  vicinity  of  this 
water  assures  the  perfect  and  equal  cooling  of  the  valve- 
seats.  This  arrangement,  while  it  renders  it  possible  to 
reduce  the  size  of  the  explosion-chamber  to  a  mini- 
mum, has  the  additional  mechanical  advantage  of  en- 
abling the  builder  to  bore  the  seats  and  'valve-guides 
with  the  same  tool,  since  they  are  all  mounted  on  the 
same  line.  From  the  standpoint  of  efficiency,  the  de- 
sign has  the  advantage  of  permitting  the  introduction 
of  the  explosive  mixture  without  overheating  it  as  it 
passes  through  the  admission-valve,  which  obtains  all 
the  benefit  of  the  cooling  of  the  cylinder-head,  literally 
surrounded  as  it  is  by  water. 

In  large  engines  the  cooling  effect  is  even  heightened 
by  separately  supplying  the  jackets  of  the  cylinder- 
head  and  of  the  cylinder.  In  engines  of  less  power  the 
top  of  the  cylinder-head  jacket  is  placed  in  communica- 
tion with  that  of  the  cylinder,  so  that  the  coldest  water 
enters  at  the  base  of  the  head  and,  after  having  there 
been  heated,  passes  around  the  cylinder  in  order  finally 
to  emerge  at  the  top  toward  the  center.  The  water  hav- 
ing been  thus  methodically  circulated,  the  useful  effect 
and  regularity  of  the  cooling  process  is  increased. 

Notwithstanding  the  care  which  is  devoted  to  water 
circulation,  it  is  advisable  to  run  the  producer-gas  en- 
gine "  colder  "  than  the  older  street-gas  types,  in  which 
the  more  economic  speed  is  that  at  which  the  water 
emerges  from  the  jacket  at  about  a  temperature  of  104 
degrees  F.  It  would  seem  advisable  to  meet  the  re- 
quirements of  piston  lubrication  by  reducing  to  a  mini- 


158    GAS-ENGINES    AND    PRODUCERS 

mum  the  quantity  of  heat  withdrawn  by  the  circulating 
water.  Indeed,  the  personal  experiments  of  the  author 
bear  out  this  principle. 

For  street-gas  engines,  however,  the  cylinders  should 
be  worked  at  the  highest  possible  temperature  consistent 
with  the  recfuirements  of  lubrication.  It  should  not  be 
forgotten  that,  in  large  engines  fed  with  producer-gas, 
economy  of  consumption  is  a  secondary  consideration, 
because  of  the  low  quantity  of  fuel  required.  The  cost, 
moreover,  may  well  be  sacrificed  to  that  steadiness  of 
operation  which  is  of  such  great  importance  in  large  en- 
gines furnishing  the  power  of  factories;  for  in  such 
engines  sudden  stops  seriously  affect  the  work  to  be 
performed.  For  this  reason  engine  builders  have  been 
led  to  the  construction  of  motors  provided  with  very 
effective  cooling  apparatus.  Since  the  circulation 
of  the  water  around  the  explosion-chamber  and  the 
cylinder  is  not  sufficient  to  counteract  the  rise  of  tem- 
perature, it  has  become  the  practice  to  cool  separately 
each  part  likely  to  be  subjected  to  heat.  The  seats  of 
the  exhaust-valves,  the  valves  themselves,  the  piston, 
and  sometimes  the  piston-rod,  have  been  provided  with 
water-jackets. 

Premature  Ignition. — Returning  to  the  causes  of  the 
discouragements  encountered  'by  some  designers  who 
endeavored  to  use  high  pressures,  it  has  already  been 
mentioned  that  premature  ignition  of  the  explosive 
mixture  in  cylinders  not  suited  for  high  pressures  is  one 
reason  for  the  bad  results  obtained.  An  explanation  of 
these  results  is  to  be  found  in  the  high  theoretical  tern- 


PREMATURE    IGNITION  159 

f 

perature  corresponding  with  great  pressures  and  in  the 
quantity  of  heat  which  must  be  absorbed  by  the  walls 
of  the  explosion-chamber.  These  two  circumstances 
are  in  themselves  sufficient  to  produce  spontaneous  igni- 
tion of  excessively  rich  mixtures,  compressed  in  an  oyer- 
heated  chamber  unprovided  with  a  sufficient  circulation 
of  water.  A  third  cause  of  premature  ignition  may  also 
be  found  in  the  old  system  of  ignition  which,  in  most 
English  engines,  consists  of  a  metallic  or  porcelain  tube, 
,the  interior  of  which  communicates  with  the  explosion- 
chamber,  an  exterior  flame  being  employed  to  heat  the 
tube  to  incandescence.  In  tubes  of  this  type  which  are 
not  provided  with  a  special  ignition-valve,  the  time  of 
ignition  is  dependent  only  on  the  moment  when  the  ex- 
plosive mixture,  driven  into  the  tube,  comes  into  con- 
tact, at  the  end  of  the  compression  stroke,  with  the  in- 
candescent zone,  thereby  causing  the  ignition.  This 
very  empirical  method  leads  either  to  an  acceleration 
or  retardation  of  the  ignition,  depending  upon  the 
temperature  of  the  tube,  the  position  of  the  red-hot  zone, 
its  dimensions,  and  the  temperature  of  the  mixture, 
which  is  determined  by  the  load  of  the  engine.  Al- 
though this  system,  the  only  merit  of  which  is  its  sim- 
plicity, may  meet  the  requirements  of  small  engines, 
there  is  not  the  slightest  doubt  that  it  is  quite  inapplica- 
ble to  those  of  more  than  20  to  25  horse -power,  for 
in  such  engines  greater  certainty  in  operation  is  de- 
manded. Even  if  only  the  more  improved  of  the  two 
types  of  hot-tube  ignition  be  considered,  with  or  with- 
out valves,  it  must  still  be  held  that  they  are  inapplica- 


160    GAS-ENGINES    AND    PRODUCERS 

ble  to  high  compression  engines.  The  ignition-valve 
is  the  part  which  suffers  most  from  the  high  tem- 
perature to  which  it  is  subjected.  Its  immediate 
proximity  to  the  incandescent  tube,  and  its  contact 
with  the  burning  gas  when  it  flares  up,  render 
it  almost  impossible  to  employ  any  cooling  arrange- 
ment. Although  writh  the  exercise  of  great  care  it  may 
work  satisfactorily  in  engines  of  normal  pressure,  it  is 
evident  that  it  cannot  meet  the  requirements  of  high- 
pressure  engines,  because  the  temperature  of  the  com- 
pressed mixture  is  such  that  the  charge  is  certain  to 
catch  fire  by  mere  contact  with  the  overheated  valve. 
In  industrial  engines  of  small  size,  premature  ignition 
has  little,  if  any,  effect  except  upon  silent  operation  and 
economic  consumption.  This  does  not  hold  true,  how- 
ever, of  large  engines.  Besides  the  inconveniences  men- 
tioned, there  is  also  the  danger  of  breaking  the  cranks 
or  other  moving  parts.  The  inertia  of  these  members  is 
a  matter  of  some  concern,  because  of  their  weight  and 
of  the  linear  speed  which  they  attain  in  large  engines. 
Some  idea  of  this  may  be  obtained  when  it  is  considered 
that  in  a  producer-gas  or  blast-furnace-gas  engine  hav- 
ing a  piston  diameter  of  24  inches  and  an  explosive 
pressure  of  299  pounds  per  square  inch,  the  force  ex- 
erted at  the  moment  of  explosion  is  about  132,000 
pounds.  Naturally,  engine  builders  have  adopted  the 
most  certain  means  of  avoiding  premature  ignition  and 
its  grave  consequences. 

The  method  of  ignition  which  at  present  seems  to  be 
preferred  to  any  other  for  producer-gas  is  that  employ- 


PRODUCER-GAS    ENGINES  161 

• 

ing  a  break-spark  obtained  with  the  magneto  apparatus 
previously  described.  Some  builders  of  large  engines, 
particularly  desirous  of  assuring  steadiness  of  running, 
have  provided  the  explosion-chamber  with  two  inde- 
pendent igniters.  It  may  be  that  they  have  adopted 
this  arrangement  largely  for  the  purpose  of  avoiding 
the  inconveniences  resulting  from  a  failure  of  one  of  the 
igniters,  rather  than  for  the  purpose  of  igniting  the 
mixture  in  several  places  so  as  to  obtain  a  more  uniform 
ignition  and  one  better  suited  for  the  propagation  of 
the  flame. 

The  Governing  of  Engines. — Various  methods  have 
been  adopted  for  the  purpose  of  varying  the  mo- 
tive power  of  an  engine  between  no  load  and  full  load, 
still  preserving,  however,  a  constant  speed  of  rotation. 
These  methods  consist  in  changing  either  the  quantity 
or  the  quality  of  the  mixture  admitted  into  the  cylinder. 
Thus  it  may  happen  that  an  engine  may  be  supplied: 

1.  With  a  mixture  constant  in  quality  and  in  quan- 
tity; 

2.  With  a  mixture  variable  in  quality  and  constant 
in  quantity; 

3.  With  a  mixture  constant  in  quality  and  variable 
in  quantity. 

I.  Mixture  Constant  in  Quality  and  Quantity. — This 
method  implies  the  use  of  the  hit-and-miss  system  of 
admission,  in  which  the  number  of  admissions  and  ex- 
plosions varies,  while  the  value  or  the  composition  of 
each  admitted  charge  remains  as  constant  as  the  com- 
pression itself  (Fig.  34) .  This  system  has  already  been 


1 62    GAS-ENGINES    AND    PRODUCERS 

referred  to  and  its  simplicity  fully  set  forth.  By  its 
use  a  comparatively  low  consumption  is  obtained,  even 
when  the  engine  is  not  running  at  full  load.  On  the 
other  hand,  it  has  the  disadvantage  of  necessitating  the 
employment  of  heavy  fly-wheel  to  preserve  cyclic  reg- 
ularity. 

2.  Mixture  Variable  in  Quality  and  Constant  in 
Quantity. — The  governing  system  most  commonly  em- 
ployed to  obtain  a  mixture  variable  in  quality  and  con- 
stant quantity  is  based  upon  the  control  of  the  gas- 
admission  valve  by  means  of  a  cam  having  a  conical 
longitudinal  section,  as  shown  in  Fig.  35.  This  cam, 
commonly  called  a  "  conical  cam,"  is  connected  with  a 
lever  actuated  from  the  governor.  As  the  lever  swings 
under  the  action  of  the  governor,  the  cam  is  shifted 
along  the  half-speed  shaft  of  the  engine.  The  result  is 
that  the  gas-admission  valve  is  opened  for  a  longer  or 
shorter  period. 

In  another  system  a  cylindrical  valve  is  mounted 
between  the  chamber  in  which  the  mixture  is  formed 
and  the  gas-supply  pipe,  the  valve  being  carried  on  the 
same  stem  as  the  mixture-valve  itself.  The  cylindrical 
valve  is  displaced  by  the  governor  so  as  to  vary  the 
quantity  of  gas  drawn  in  with  relation  to  the  quantity 
of  air. 

When  the  engines  are  fed  with  producer-gas  the 
parts  which  have  just  been  described  should  be  fre- 
quently inspected  and  cleaned ;  for  they  are  only  too 
easily  fouled. 

Engines  thus  governed  should  be  run  at  high  pres- 


PRODUCER-GAS    ENGINES  163 

sure  so  as  to  insure  the  ignition  of  the  producer-gas 
mixtures  formed  when  the  position  of  the  cam  cor- 
responds with  the  minimum  opening  of  the  gas-valve. 
Powerful  governors  should  be  employed,  capable  of 
overcoming  the  resistance  offered  by  the  cylindrical 
valve  or  the  cam. 

It  may  often  happen  that  variations  in  the  load  of  the 
engine  render  it  necessary  to  actuate  the  air  valve,  so 
as  to  obtain  a  mixture  which  will  be  ignited  and  ex- 
ploded under  the  best  possible  conditions. 

3.  Mixture  Constant  in  Quality  and  Variable  in 
Quantity. — In  supplying  an  engine  with  a  mixture  con- 
stant in  quality  and  variable  in  quantity,  the  compres- 
sion does  not  remain  constant.  The  quantity  of  mixture 
drawn  in  by  the  cylinder  may  even  be  so  far  reduced 
that  the  pressure  drops  below  the  point  at  which  igni- 
tion takes  place.  For  that  reason  engines  of  this  type 
should  be  run  at  high  pressures. 

The  variation  of  the  quantity  of  mixture  may  be 
effected  in  various  ways.  The  simplest  arrangement 
consists  in  mounting  a  butterfly-valve  in  the  mixture- 
pipe,  which  valve  is  controlled  by  the  governor  and 
throttles  the  passage  to  a  greater  or  lesser  degree. 
A  very  striking  solution  of  the  problem  consists  in  vary- 
ing the  opening  of  the  mixture-valve  itself.  To  attain 
this  end  the  valve  is  moved  by  levers.  The  point  of 
application  of  one  of  these  levers  is  displaced  under 
the  action  of  the  governor  so  as  to  vary  the  travel  of 
the  valve  within  predetermined  limits.  Under  these 
conditions  a  mixture  of  constant  homogeneity  is  intro- 


1 64    GAS-ENGINES    AND    PRODUCERS 

duced  into  the  cylinder,  so  proportioned  as  to  insure 
ignition  even  at  low  pressures. 

In  recent  experiments  conducted  by  the  author  it  was 
proved  that  with  this  governing  system  ignition  still 
takes  place  even  though  the  pressure  has  dropped  to 


FIG.  760. — Governing  system  for  producer-gas  engines. 

43  pounds  per  square  inch.  This  system  has  the  merit 
of  rendering  it  possible  to  employ  ordinary  governors 
of  moderate  size,  since  the  resistance  to  be  overcome 
at  the  point  of  application  of  the  lever  is  comparatively 
small.  In  the  accompanying  illustration  the  Otto 
Deutz  system  is  illustrated. 


CHAPTER  XI 


PRODUCER-GAS 

IT  may  here  be  not  amiss  to  point  out  the  differences 
between  illuminating  gas  and  those  gases  which  are 
called  in  English  "  producer  "  gases,  and  in  French 
"  poor  "  gases,  because  of  their  low  calorific  value. 

Street -Gas. — This  gas,  the  composition  of  which 
varies  with  different  localities,  has  a  calorific  value, 
which  is  a  function  of  its  composition,  and  which  varies 
from  5,000  to  5,600  calories  per  cubic  meter  (19,841  to 
24,896  B.  T.  U.  per  35.31  cubic  feet)  measured  at  con- 
stant pressure  and  corrected  to  o  degrees  C.  (32  degrees 
F.)  at  a  pressure  of  760  millimeters  (29.9  inches  of 
mercury,  or  .atmospheric  pressure),  not  including  the 
latent  heat  of  the  water  of  condensation.  The  follow- 
ing table  gives  the  average  volumetric  composition  of 
illuminating  gas  in  various  cities: 


CITIES. 

/ 

London. 

Manches- 
ter. 

New 
York. 

Paris. 

Berlin. 

Hydrogen 

48 

4.6 

4O 

C2 

co 

Carbon  monoxide  

4 

T" 

7 

4 

6 

q 

Methane                            

38 

3  C 

T.J 

32 

T.  T. 

Various  hydrocarbons 

4 

6 

7 

6 

C 

Carbon  dioxide    

4 

T. 

2 

Nitrogen                            

- 

2 

8 

4 

I 

Oxygen 

j 

.  I 

100 

100 

IOO 

IOO 

IOO 

165 


166    GAS-ENGINES    AND    PRODUCERS 

Furthermore,  these  constituents  vary  within  certain 
limits.  This  is  also  true  of  the  calorific  value.  Experi- 
ments made  by  the  author  have  demonstrated  that  in 
the  same  place  at  an  interval  of  a  few  hours,  variations 
of  approximately  ten  per  cent,  occur. 

Composition  of  Producer-Gases.  -  The  average 
chemical  composition  of  producer-gases  varies  with  the 
conditions  under  which  they  are  generated  and  the  na- 
ture of  the  fuel.  The  following  are  the  proportions  of 
its  constituents  expressed  volumetrically : 


G 

AS. 

Blast 
Furnace. 

Producer. 

Mond. 

Mixed 

(Fichet)  . 

Water 
(Strache). 

Wood 
(Riche). 

Nitrogen  and  oxygen.  .  .  . 
Carbon  monoxide  
Carbon  dioxide  . 

60 
24 
I  2 

59 

25 
c 

42 
I  I 

16 

5° 

20 

7 

5 

40 

I 
29 
I  i 

Hydrocarbons 

2 

2 

2 

3 

I 

I  r 

Hydrogen  .  .  .... 

2 

q 

2Q 

j 

2O 

CQ 

1  ) 

A  A 

100 

100 

100 

100 

100 

100 

Calorific  value  in  calories. 
Average  weight  of  a  cubic 
meter  in  kilos  . 

950 
I.  3O 

1,100 
I.  IO 

1,400 
I  .02 

1,300^ 

• 
I.OC 

2,400 

o  680 

2,960 

o  824 

Or   of  a    cubic    foot    in 
pounds  

O.OO8 

O.OO7 

O.OO6 

•w  J 
0.0068 

0.0042 

O  OO  C  I 

Blast-furnace  gas  has  been  used  for  generating  power 
by  means  of  gas-engines  for  about  ten  years.  At  the 
present  time  it  is  used  in  engines  of  very  high  power, 
a  discussion  of  which  engines  more  properly  belongs 
to  a  work  on  metallurgy,  and  has  no  place,  therefore, 
in  a  manual  such  as  this. 

Producer-gas,  in  the  true  sense  of  the  term,  is  gen- 
crated  in  special  apparatus  either  under  pressure  or  by 


PRODUCER-GAS  167 

•   . 

suction  in  a  manner  to  be  described  in  the  following 
chapters. 

Mond  gas  is  produced  in  generators  of  the  blowing 
or  pressure  type  from  bituminous  coal,  necessitating  the 
employment  of  special  purifiers  and  permitting  the  col- 
lection of  the  by-products  of  the  fractional  distillation 
of  the  coal.  Mond  gas  plants  are,  therefore,  rather 
complicated  and  can  be  advantageously  utilized  only 
for  large  engines.  More  exhaustive  information  can 
be  obtained  from  the  descriptions  published  by  the 
builders  of  Mond  gas  generators. 

Mixed  gas  is  generated  in  apparatus  arranged  so  that 
the  retort  is  kept  at  a  high  temperature,  thereby  produc- 
ing a  gas  richer  in  hydrogen  than  that  made  by  pro- 
ducers. It  should  be  observed  that  in  practice  the  gen- 
erators at  present  used  yield  a  producer-gas,  the  calo- 
rific value  of  which  fluctuates  between  1,000  and  1,400 
calories  per  cubic  meter  (3,968  to  5,158  B.  T.  U.  per 
35.31  cubic  feet)  ;  and  the  composition  varies  accord- 
ingly, in  the  manner  that  has  already  been  indicated 
in  the  tables  for  producer-gas  and  mixed  gas.  There 
is  no  necessity,  therefore,  for  drawing  a  distinction  be- 
tween these  two  qualities  of  gas. 

Water-gas  should  theoretically  be  composed  of  50 
per  cent,  carbon  monoxide  and  50  per  cent,  hydrogen, 
resulting  from  the  decomposition  of  steam  by  in- 
candescent coal.  In  practice,  however,  it  contains  a 
little  nitrogen  and  carbon. dioxide.  The  gas  is  obtained 
from  generators  in  which  air  is  alternately  blown  in  to 
fan  the  fire  and  then  steam  to  produce  gas.  Water-gas 


1 68    GAS-ENGINES    AND    PRODUCERS 

is  employed  in  soldering  on  account  of  its  reducing 
properties  and  of  the  high  temperature  of  its  flame. 
The  great  quantity  of  carbon  monoxide  which  it  con- 
tains renders  it  very  poisonous  and  exceedingly  danger- 
ous, because  it  is  generated -under  pressure.  From  the 
economical  standpoint,  its  generation  is  more  expen- 
sive than  that  of  producer-gas,  for  which  reason  its 
employment  in  gas-engines  is  hardly  of  much  value. 

Wood-gas,  the  composition  of  which  has  already  been 
given,  is  generated  in  apparatus  of  the  Riche  type,  the 
principle  of  which  consists  in  heating  a  cast  retort 
charged  with  any  kind  of  fuel,  namely  wood,  and  ver- 
tically mounted  on  a  masonry  base. 

This  apparatus  should  be  of  .particular  interest  to 
the  proprietors  of  sawmills,  furniture  factories,  and  the 
like,  since  it  offers  a  means  of  using  the  waste  products 
of  their  plants. 

The  relatively  high  proportion  of  carbon  monoxide 
in  producer-gas  is  objectionable  from  a  hygienic  stand- 
point, so  much  so,  indeed,  that  it  has  attracted  the  atten- 
tion of  manufacturers.  Carbon  monoxide,  the  specific 
gravity  of  which  is  0.967,  is  a  gas  peculiarly  poisonous 
and  dangerous.  It  cannot  be  breathed  without  baneful 
effects,  and  is  even  more  dangerous  than  carbonic-acid 
gas,  which  eventually  causes  asphyxiation  by  reducing 
the  quantity  of  oxygen  in  the  air.  For  this  reason,  it  is 
necessary  to  take  the  utmost  precaution  in  efficiently  and 
continuously  ventilating  the  rooms  in  which  the  gas- 
generators  and  their  accessories  are  installed.  This 
suggestion  should  be  followed,  above  all,  when  the  ap- 


ASPHYXIATION  160 

f  ' 

paratus  in  question  are  installed  in  cellars  and  base- 
ments. As  a  further  precaution,  where  the  plant  is 
rather  large  a  workman  should  not  be  allowed  to  enter 
the  generator  room  alone. 

Blowing-generators,  or  those  in  which  the  gas  is  pro- 
duced under  pressure,  are  more  dangerous  than  suc- 
tion-generators. In  the  former  a  leaky  joint  may  cause 
the  vitiation  of  the  surrounding  air  as  the  producer-gas 
escapes;  in  the  suction  apparatus  the  same  fault  simply 
causes  more  air  to  be  drawn  in. 

Dr.  Melotte  recommends  the  following  procedure 
in  cases  of  carbon  monoxide  asphyxiation: 

CARBON  MONOXIDE  ASPHYXIATION 

Cases  of  poisoning  by  carbon  monoxide  are  both  fre- 
quent and  dangerous.  The  gas  is  extremely  poisonous, 
and  all  the  more  dangerous  because  it  is  odorless,  color- 
less and  tasteless.  When  it  comes  into  contact  with  the 
blood,  it  forms  a  combination  so  stable  that  it  is  reacted 
upon  by  the  oxygen  of  the  air  only  with  difficulty.  It 
follows,  therefore,  that  with  each  respiration  of  air 
charged  with  carbon  monoxide,  a  certain  quantity  of 
blood  is  poisoned.  In  consequence  of  this,  there  is  a 
possibility  of  poisoning  in  open  air. 

Symptoms. — The  symptoms  observed  will  vary  with 
the  manner  in  which  the  blood  has  been  poisoned. 
There  are  two  ways  in  which  this  poisoning  can  occur. 
The  one  depends  upon  whether  the  atmosphere  contains 
an  excess  of  carbon  monoxide;  the  other  whether  the 
air  breathed  contains  only  traces  of  the  gas. 


170    GAS-ENGINES    AND    PRODUCERS 

Gradual,  Rapid  Asphyxiation. — At  first  a  vague 
sickness  is  felt,  rapidly  followed  by  violent  headaches, 
vertigo,  anxiety,  oppression,  dimness  of  vision,  beating 
of  the  pulse  at  the  temples,  hallucinations,  and  an  irre- 
sistible desire  to  sleep.  If  at  this  stage  the  patient  has  a 
sufficient  idea  of  danger  to  prompt  him  to  open  a 
window  or  door,  he  will  escape  death. 

In  the  second  stage,  the  victim's  legs  are  paralyzed, 
but  he  can  still  move  his  arms  and  his  head.  The  mind 
still  preserves  its  clearness,  and  in  a  measure  assists  the 
further  process  of  asphyxiation  because  of  its  impo- 
tency.  Then  follow  coma  and  death. 

Slow,  Chronic  Asphyxiation. — Slow,  chronic  as- 
phyxiation is  not  infrequent.  Its  symptoms  are  often 
difficult  to  detect.  Poisoning  is  manifested  by  weak- 
ness, cephalalgia,  vomiting,  pallor,  general  anemia,  las- 
situde, and  local  paralysis.  If  any  of  these  symptoms 
appear  in  the  men  who  work  in  the  vicinity  of  the  pro- 
ducers, immediate  steps  should  be  taken  to  prevent  the 
possibility  of  carbon  monoxide  asphyxiation. 

FIRST  AID  IN  CASES  OF  CARBON  MONOXIDE  POISONING 

It  has  already  been  stated  that  the  oxygen  of  the  air 
has  no  oxidizing  effect  upon  blood  contaminated  by 
carbon  monoxide.  Only  a  liberal  current  of  pure 
oxygen  can  oxidize  the  combination  formed  and  render 
hematosis  possible.  This  liberal  current  can  be  ob- 
tained from  an  oxygen  tank  of  the  portable  variety,  pro- 
vided with  a  tube  carrying  at  its  free  end  a  mask  which 


METHODS    OF    RESUSCITATION      171 

is  held  over  the  mouth  and  the  nostrils.  The  absorption 
of  gas  takes  place  by  artificial  respiration,  which  is 
effected  in  several  ways.  The  most  practical  of  these 
are  the  Sylvester  and  Pacini  methods. 

Sylvester  Method. — The  patient  is  laid  on  his  back. 
His  arms  are  raised  over  his  head  and  then  brought 
back  on  each  side  of  the  body.  This  operation  is  re- 
peated fifteen  times  per  minute  approximately.  The 
method  is  very  frequently  employed  and  is  excellent  in 
its  results. 

The  Pacini  Method.  —Four  fingers  are  placed  in 
the  pit  of  the  arm,  with  the  thumb  on  the  shoulder. 
The  shoulder  is  then  alternately  raised  and  lowered, 
producing  a  marked  expansion  of  the  chest.  This 
method  is  the  more  effective  of  the  two.  The  move- 
ments described  are  repeated  fifteen  to  twenty  times 
each  minute  very  rhythmically. 

One  or  the  other  of  these  two  methods  of  treatment 
should  be  .immediately  applied  in  serious  cases.  Cer- 
tain preliminary  precautions  should  be  taken  in  all 
cases,  however.  The  patient  should  be  carried  to  a  well- 
ventilated  and  moderately  heated  room,  stripped  of  his 
clothes,  and  warmed  by  water-bottles  and  heated  linen. 
Reflex  action  should  be  excited,  the  peripheral  nervous 
system  stimulated  in  order  to  contract  the  heart  and  the 
respiratory  muscles,  and  the  precordial  region  cauter- 
ized. In  addition  to  this  treatment,  the  region  of  the  dia- 
phragm should  be  rubbed  and  pinched,  the  skin  rubbed, 
cold  showers  given,  flagellations  administered,  urtica- 
tions  (whipping  with  nettles)  undertaken,  the  skin  and 


172    GAS-ENGINES    AND    PRODUCERS 

the  mucous  membranes  excited,  the  mucous  membrane 
of  the  nose  and  of  the  pharynx  titillated  with  a  feather 
dipped  in  ammonia,  alcohol,  vinegar,  or  lemon  juice. 

Rhythmic  traction  of  the  tongue  is  effective  when  car- 
ried out  as  follows :  The  tongue  is  seized  with  a  forceps 
and  kept  extended  by  means  of  a  coarse  thread.  It  is 
then  pulled  out  from  the  mouth  sharply  and  allowed  to 
reenter  after  each  traction.  These  movements  should 
be  rhythmic  and  should  be  repeated  fifteen  to  twenty 
times  a  minute. 

All  these  efforts  should  be  continued  for  several 
hours.  When  the  patient  has  finally  been  revived,  he 
should  be  placed  in  a  warm  bed.  Stimulants  such  as 
wine,  coffee,  and  the  like  should  be  administered.  If 
the  head  should  be  congested,  local  blood-letting  should 
be  resorted  to  and  four  or  six  leeches  applied  behind 
the  ears.  It  should  be  borne  in  mind  that  the  various 
steps  enumerated  are  to  be  taken  pending  the  arrival 
of  a  physician. 

IMPURITIES  OF  THE  GASES 

Most  of  the  coal  used  in  generating  producer-gas 
contains  sulphur.  Sulphuretted  hydrogen  is  thus  pro- 
duced, which  mixes  with  the  gas  and  imparts  to  it  its 
characteristic  odor.  In  some  gas-generators,  purifiers 
are  employed  in  which  sawdust  mixed  with  iron  salts 
is  utilized,  with  the  result  that  a  combination  is  formed 
with  the  sulphuretted  hydrogen,  thereby  removing  it 
from  the  producer-gas.  In  other  forms  of  generators 


SULPHURETTED    HYDROGEN        i 


73 


a  more  summary  method  of  purification  is  adopted,  so 
that  traces  of  sulphuretted  hydrogen  still  remain. 
Since  this  gas  attacks  copper,  the  employment  of  this 
metal  is  not  advisable  for  the  following  apparatus: 
Generator  (openings,  cock  for  testing  the  gas)  ;  piping 
(gas-pressure  cocks,  drain  and  pet  cocks)  ;  engine  (gas- 
admission  cock,  lubricating  joint  in  the  cylinder,  valves 
and  cocks  of  the  compressed-air  starting-pipe). 

The  distillation  of  coal  in  generators  results  in  the 
formation  of  ammonia  gas.  This  also  has  a  corrosive 
action  on  copper  and  its  alloys ;  but  owing  to  its  great 
solubility,  it  is  eliminated  by  the  waters  of  the  "  scrub- 
ber "  and  does  not  reach  the  engine. 

PRODUCTION  AND  CONSUMPTION 

The  quantity  of  gas  produced  in  most  generators 
varies  from  6.4  to  8.2  pounds  per  cubic  foot  of  raw  coal 
burnt  in  the  generator.  The  engine  consumes  per 
horse-power  per  hour  70  to  115  cubic  feet  of  gas,  de- 
pending upon  its  richness. 


CHAPTER  XII 

PRESSURE  GAS-PRODUCERS 

As  we  have  already  seen,  producer-gas  as  a  fuel  for 
engines  may  be  generated  in  two  kinds  of  apparatus,  the 
one  operating  under  pressure,  and  the  other  by  suction. 

Dowson  Gas-Producers. — The  first  pressure-gen- 
erators were  introduced  by  Dowson  of  London  and 
necessitated  installations  of  quite  a  complicated  nature. 
Later  improvements  made  by  the  designers  contrib- 
uted much  to  the  general  employment  of  their  system. 
Many  installations  varying  from  50  to  100  horse- 
power and  more  may  be  found  in  the  United  Kingdom, 
all  of  them  made  by  Dowson.  Indeed,  for  a  long  time 
the  name  of  Dowson  was  coupled  with  producer-gas 
itself.  The  Dowson  system  necessitates  the  utilization 
of  anthracite  or  of  comparatively  hard  coal,  such  as 
that  mined  in  Wales  and  Pennsylvania.  Owing  to  the 
necessity  of  employing  this  special  quality  of  coal  the 
Dowson  system  and  the  systems  that  sprang  from  it 
were  burdened  with  cooling,  washing,  and  purifying 
apparatus,  which  complicated  the  installations  to  such 
an  extent  that  they  resembled  gas  works.  The  genera- 
tor that  took  the  place  of  the  retort  was  fed  with  air 
and  steam,  blown  in  under  pressure,  necessitating  the 

employment  of  a  boiler.    Furthermore,  the  production 

174 


DOWSON    GAS-PRODUCERS 


'75 


of  the  gas  under  pressure  necessitated  the  use  of  a  gas- 
ometer for  its  collection  before  it  was  supplied  to  the 
engine-cylinder.  Such  installations  were  evidently 


costly,  and  were,  moreover,  difficult  to  maintain  in 
proper  working  order.  Nevertheless,  there  are  many 
cases  in  which  they  must  be  industrially  employed. 


THE    GENERATOR 


177 


Among  these  may  be  cited  works  in  which  producer- 
gas  is  employed  as  a  furnace  fuel  or  as  a  soldering  or 
roasting  medium.  Still  other  cases  are  those  in  which 
the  producer-gas  must  be  piped  to  some  distance  from 
a  central  generating  installation  to  various  engines, 
in  the  manner  rendered  familiar  in  gas-lighting  prac- 
tice. 

Most  pressure  gas-generators  have  been  copied  from 
the  original  type  invented  by  Dowson.  These  include 
a  generator  in  which  the  gas  is  produced;  an  injector 
fed  by  a  boiler;  a  fan  or  a  compressor  by  means  of 
which  a  mixture  of  steam  and  air  is  blown  under  the 
generator-furnace;  washing  apparatus  termed  "  scrub- 
bers"; gas-purifying  apparatus;  and  a  gas-holder 
(Fig.  77). 

Generators. — The  generator  consists  of  a  retort  made 
of  refractory  clay,  vertically  mounted,  and  cylindrical 
or  conical  in  form.  This  retort  is  protected  on  its  ex- 
terior by  a  metal  jacket  with  an  intermediate  layer  of 
sand  which  serves  to  reduce  the  heat  lost  by  radiation. 
The  fuel  is  charged  through  the  top  of  the  retort,  which 
is  provided  with  a  double  closure  in  order  to  prevent 
the  entrance  of  air  during  the  charging  operation.  The 
generator  rests  on  a  grid  arranged  at  the  base  of  the 
retort,  upon  which  grid  the  ashes  fall.  The  outlet  of 
the  injector-pipe  opens  into  the  ash-pit,  and  this  injector 
constantly  supplies  a  mixture  of  steam  and  air.  The 
mixture  is  generally  superheated  by  passing  it  through 
a  coil  arranged  in  the  fire-box  of  the  boiler,  in  the  gen- 
erator, or  in  the  outlet  for  burnt  gases.  Sometimes  the 


178    GAS-ENGINES    AND    PRODUCERS 

air  is  subjected  to  a  preliminary  heating  by  recuperat- 
ing in  some  way  the  waste  heat  of  the  apparatus. 

The  chief  features  in  the  arrangement  of  generators 
which  have  received  the  attention  of  manufacturers  are 
the  following:  Good  distribution  of  the  fuel  in  charg- 
ing; easy  descent  of  the  fuel;  reduction  of  the  destruc- 
tive action  of  the  clinkers  on  the  walls ;  means  for  clean- 
ing the  grate  without  interfering  with  the  generation  of 
gas;  prevention  of  leakage.  Many  devices  have  been 
employed  to  fulfil  these  requisites. 

A  perfect  distribution  of  the  fuel  during  charging  is 
attained  chiefly  by  the  form  of  the  hopper,  and  of  its 
gate,  which  is  generally  conical.  In  most  apparatus 
the  gate  opens  toward  the  interior  of  the  generator,  and 
the  inclination  of  its  walls  causes  a  uniform  scattering 
of  the  fuel  in  the  retort.  It  is  all  the  more  necessary  to 
disperse  the  fuel  in  this  manner  when  the  cross-section 
of  the  retort  is  small  compared  with  its  height. 

The  facility  of  the  fuel's  descent  is  dependent  largely 
upon  the  nature  and  the  size  of  the  coal  employed. 
Porous  coal  gives  better  results  than  dense  and  compact 
coal.  It  is  therefore  preferable  to  employ  screened 
coal  free  from  dust  in  pieces  each  the  size  of  a  hazel- 
nut.  The  various  sections  given  to  the  interior,  includ- 
ing as  they  do  cylindrical  forms,  truncated  at  the  sum- 
mit or  the  base,  partially  truncated  toward  the  base 
and  the  like,  would  lead  to  the  conclusion  that  this 
question  is  not  of  the  importance  \vhich  some  writers 
would  have  us  believe.  Still,  it  must  be  considered  that 
if  the  fuel  drops  slowly,  its  prolonged  detention  within 


CLEANLINESS 


179 


the  walls  of  the  hopper  and  its  transformation  into 
fusible  slag  may  result  in  a  disintegration  of  the  re- 
fractory lining  of  the  furnace. 

The  quantity  of  steam  injected,  greater  or  less,  ac- 
cording to  the  nature  of  the  fuel,  renders  it  possible  to 
obtain  friable  slags  and  consequently  to  prevent  grave 
injury  to  the  retort.  Red-ash  coal  is  in  general  fusible, 
containing  as  it  does  some  iron.  Its  temperature  of 
fusion  varies  between  1,832  to  2,732  degrees  F. 

Cleanliness  is  most  important  so  far  as  the  opera- 
tion of  the  generator  is  concerned.  It  should  be  pos- 
sible to  scrape  the  generator  during  operation  without 
changing  the  composition  of  the  gas,  when  the  incan- 
descent zone  is  chilled,  or  an  excess  of  air  is  introduced, 
or  the  steam-injector  be  momentarily  thrown  out  of 
operation.  Mechanical  cleaners  with  movable  grates 
or  revolving  beds  have  the  merit  of  causing  the  ashes 
to  drop  without  interfering  with  the  operation  of  the 
apparatus.  The  same  meritorious  feature  is  character- 
istic of  ash-pits  having  water-sealed  joints. 

Pressure  gas-generators  need  not  be  as  perfectly  gas- 
tight  as  suction  apparatus.  Leakage  of  gas,  which  is 
usually  manifested  by  a  characteristic  odor,  results  in  a 
loss  of  consumption  and  renders  the  air  unfit  to  breathe. 

A  generator  should  be  provided  in  its  upper  part 
with  openings  through  which  a  poker  can  easily  be  in- 
troduced in  order  to  shake  up  the  fuel  and  to  dislodge 
the  clinkers  which  tend  to  form  and  which  cause  the 
principal  defects  in  operation,  particularly  with  fuels 
that  tend  to  swell,  cake,  and  adhere  to  the  furnace  walls 


i8o    GAS-ENGINES    AND    PRODUCERS 

when  heated.  Many  apparatus,  moreover,  are  pro- 
vided with  lateral  openings  having  mica  panes  through 
which  the  progress  of  combustion  can  be  observed 

(Fig.  79). 
Air-Blast. — The  system  by  which  air  and  steam  are 


FIG.  79. — Fichet-Heurtey  producer  with  rotating  bed-plate. 

injected  necessitates  the  employment  of  a  steam-boiler 
of  75  pounds  pressure.  This  method  of  blowing,  which 
is  rather  complicated,  has  the  disadvantage  of  varying 


BLOWERS:   THEIR   NECESSITY       181 

• 

in  feed  with  the  pressure  of  the  steam  in  the  boiler, 
which  pressure  is  not  easily  maintained  at  a  given  num- 
ber of  pounds  per  square  inch.  Moreover,  when  more 
or  less  resistance  is  offered  by  the  fuel  in  the  generator 
the  quantity  of  air  which  is  injected  is  likely  to  be 
diminished  in  quantity  while  the  quantity  of  steam  re- 
mains the  same.  The  result  is  a  change  in  speed  which 
follows  from  the  modification  of  the  proportions  of  the 
two  elements.  For  these  reasons  some  manufacturers 


FIG.  80. — Koerting  blower. 

have  resorted  of  late  years  to  the  employment  of  fans 
.and  blowers. 

Blowers. — The  fans  or  blowers  employed  vary  con- 
siderably in  arrangement.  Most  of  them  are  based  on 
the  Koerting  system  (Fig.  80),  and  comprise  essentially 
(i)  a  tube  through  which  the  steam  is  supplied  under 
pressure,  and  (2)  a  cylindro-conical  blast-pipe.  The 
tube  is  placed  in  the  axis  of  the  blast-pipe  at  its  outer 
opening.  As  it  escapes  under  pressure  the  steam  is 
caught  in  the  blast-pipe  and  draws  with  it  a  certain 
quantity  of  air,  which  can  be  regulated.  It  is  important 
that  these  injection  blowers  should  operate  in  such  a 
manner  that  the  pressure  and  the  feed  of  air  and  steam 
can  be  controlled. 

Fans. — Mechanical  blowers  have  the  advantage  of 


1 82    GAS-ENGINES    AND    PRODUCERS 

dispensing  with  the  employment  of  steam  under  pres- 
sure and  the  consequent  installation  of  a  boiler  (Fig. 
78) .  Driven  by  the  engine  itself  or  from  some  separate 
source  of  power,  these  apparatus  are  easily  placed  in 
position,  require  no  great  amount  of  attention,  and  util- 
ize but  little  energy.  They  are  either  of  the  centrif- 
ugal type  or  of  the  rotary  type,  exemplified  in  the  Root 
blower  (Fig.  81).  The  latter  system  has  the  advantage 


FIG.  81.— Root  blower. 

of  high  efficiency,  and  of  enabling  comparatively  high 
pressures — 19  to  27  inches  of  water — to  be  attained, 
which,  however,  are  used  only  for  special  fuels,  such 
as  lignite,  peat,  and  the  like.  The  air  supplied  by  the 
blower,  before  reaching  the  fire-box,  is  superheated, 
either  before  or  after  it  is  charged  with  steam. 

Compressors. — In  some  installations  air  is  supplied 
by  compressor  under  the  high  pressure  of  70  to  90 
pounds  per  square  inch,  and  seem  well  adapted  to  the 
production  of  a  gas  of  good  quality.  Moreover,  neither 


EXHAUSTERS 


'83 


tar  nor  ammoniacal  waters  are  produced.  The  Gardie 
producer  may  be  considered  typical  of  this  class  of  ap- 
paratus (Fig.  82).  The  chief  feature  of  this  producer 
is  to  be  found  in  simple  washing  and  purifying  appara- 
tus. It  may  be  well  to  state  here  that  the  compression 
of  air  at  high  pressure  occasions  some  complications, 
and  a  considerable  expenditure  of  power. 


FIG.  82. — Gardie  producer. 

Exhausters. — Some  designers  have  invented  devices 
which  draw  gas  into  the  generator  whence  it  is  sup- 
plied to  the  engines,  these  suction  apparatus  being 
connected  with  the  blowers  or  used  separately.  But 
with  the  exception  of  a  few  special  instances,  such  ar- 
rangements are  not  widely  used — at  least  not  for  the 
production  of  motive  power  alone. 

Whatever  may  be  the  arrangement  employed  for  the 


1 84    GAS-ENGINES    AND    PRODUCERS 

introduction  of  a  mixture  of  air  and  steam  under  the 
grate  of  the  generator,  the  blast-pipe  as  a  general  rule 
discharges  toward  the  center  of  the  apparatus.  Still,  in 
large  producers  it  becomes  desirable  to  provide  a  means 
for  varying  the  quantity  of  air  and  steam  within  wide 
limits  so  as  to  regulate  the  heat  of  the  fire.  For  that 
reason  several  outlets  are  symmetrically  arranged  be- 
low the  fuel. 
Washing  and  Purifying. — In  pressure  producers 


FIG.  83. — Sawdust  purifier. 

the  gas  is  generally  washed  and  purified  with  much 
more  care  than  in  suction  apparatus.  Given  a  sufficient 
pressure,  the  gas  can  be  driven  through  the  different 
apparatus  and  the  spaces  between  the  material  which 
they  contain  without  any  difficulty.  The  gases  emerge 
from  the  generator  highly  heated,  and  this  heat  is  used 
either  to  warm  the  injection  water  or  to  generate  the 
steam  fed  to  the  furnace.  The  gases  then  enter  the 


WASHING    AND    PURIFYING         185 

*  9 

washing  apparatus,  which  most  frequently  consists  of 
a  succession  of  contrivances  in  which  the  gas  is  washed 
either  by  causing  it  to  bubble  up  through  the  water,  or 
by  subjecting  it  to  superficial  friction  against  a  sheet  of 
water,  or  by  systematically  circulating  it  in  a  mass  of 
continuously  besprinkled  inert  material.  The  object  of 
washing  is  to  remove  the  dust  contained  in  the  gas  and 


FIG.  84. — Moss  or  fiber  purifier. 

to  precipitate  it  in  the  form  of  a  slime  which  can  be  re- 
moved by  flushing. 

Physical  purification  thus  begun  is  completed  by 
passing  the  gas  through  a  filtering  bed  consisting  of 
fiber,  sawdust,  or  moss  ( Figs.  83  and  84) .  Chemical  puri- 
fication, if  it  is  necessary,  is  effected  by  means  of  cal- 
cium hydrate,  iron  oxide,  or,  still  better,  by  a  mixture 
of  lime  and  iron  sulphate.  This  filtering  material  must 
necessarily  be  renewed  after  it  is  exhausted. 


1 86    GAS-ENGINES    AND    PRODUCERS 

Gas -Holder. — The  gas-holder  is  composed  essen- 
tially of  a  tank  and  a  bell.  Sometimes,  for  the  purpose, 
of  simplifying  the  apparatus,  the  tank  is  so  arranged  as 


FIG.  85. — Combined  gas-holder  and  washer. 

to  take  the  place  of  a  washer  or  scrubber  (Fig.  85). 
The  bell  should  be  provided  with  mechanism  which, 
when  the  bell  is  full,  automatically  diminishes  or  stops 
the  generation  of  gas.  It  is  advisable  to  provide  the 


GAS-HOLDER    DESIGN  187 

bell  with  a  blow  or  flap  valve  opening  toward  the  inte- 
rior. If,  therefore,  it  should  happen  that  the  gas  sup- 
ply is  cut  off  while  the  engine  still  continues  to  run, 
the  suction  of  the  engine  will  not  draw  the  water  from 
the  tank  of  the  gas-holder. 

When  engines  are  employed  the  horse-power  of  which 
does  not  exceed  50,  it  is  sometimes  customary  to  use 
the  water  of  the  tank  (placed  at  a  higher  elevation  than 
the  engine)  to  cool  the  cylinder.  In  this  manner  the 
cost  of  installing  special  reservoirs  is  saved.  If  such 
an  arrangement  be  employed,  however,  the  quantity  of 
water  contained  in  the  tank  should  be  at  least  double 
that  ordinarily  contained  in  reservoirs.  If  this  precau- 
tion be  not  observed,  the  water  may  become  excessively 
heated  and  expand  the  gas  in  the  bell. 

The  volume  of  the  bell  of  the  gas-holder  should 
preferably  be  not  less  than  about  3  cubic  feet  per  effec- 
tive horse-power  of  the  engine  to  be  supplied.  Under 
these  circumstances  the  bell  acts  as  a  pressure-regulator, 
assures  a  sufficient  homogeneity  of  the  remaining  gas, 
and  renders  it  possible  to  supply  the  engine  during  the 
short  intervals  in  which  it  is  necessary  to  stop  the  blast 
to  poke  the  fire.  But  if  the  engine  consumes  60  to 
80  cubic  feet  of  producer-gas  per  horse-power  per 
hour,  the  bell  must  be  very  much  larger  in  size  if  the 
generation  of  gas  is  to  be  checked  for  some  time 

It  may  be  well  to  recall  here  that  coal  is  not  the  only 
fuel  which  lends  itself  to  the  generation  of  gas  suitable 
for  driving  engines,  but  that  some  generators  are  able  to 
utilize  lignite,  peat,  and  the  like.  In  others,  straw, 


1 88    GAS-ENGINES    AND    PRODUCERS 

wood,  shavings  and  sawdust,  tannery  waste,  and  other 
organic  matter  is  burnt  with  an  efficiency  very  much 
higher  than  that  which  they  would  give  in  the  fire- 
boxes of  steam-boilers. 

Lignite  and  Peat  Producers. — Lignite  and  peat 
generators  (Fig.  86)  cannot  operate  on  the  suction 
principle  because  of  the  resistance  offered  to  the  pas- 
sage of  gas  by  the  layer  of  fuel.  This  resistance  is  con- 
siderable and  extremely  variable.  Consequently,  lig- 


FIG.  86. — Otto  Deutz  lignite-producer. 

nite  and  peat  generators  must  operate  on  the  pressure 
principle  by  utilizing  a  blast  of  air  or  a  steam  injector, 
depending  upon  the  amount  of  water  contained  in  the 
lignite.  As  a  general  rule  a  Root  blower  operating  at 
a  pressure  of  8  to  27  inches  of  water,  depending  upon 
the  quality  of  the  lignite,  is  employed.  These  genera- 
tors are  not  to  be  recommended  for  powers  less  than 
50  horse-power,  for  the  cost  of  the  apparatus  becomes 
too  great. 


LIGNITE    AND    PEAT    PRODUCERS    189 

,  9 

The  best  lignite  is  that  which,  after  combustion, 
leaves  a  fine  ash  and  no  agglomerated  clinker.  Lig- 
nite has  the  peculiarity  of  forming  dust  which  ignites 
very  easily  when  air  is  admitted  into  the  generator. 
For  this  reason  the  generator  should  not  be  scraped 
during  operation,  in  order  to  avoid  the  production  of 
a  flame  which  may  escape  from  the  apparatus. 

The  scrubber  is  simply  a  column  without  coke, 
and  is  provided  with  an  interior  sprinkler.  The 
coke  is  too  rapidly  clogged  with  tar.  Much  of 
this  tar  is  deposited  in  a  chamber  which  precedes  the 
gas-holder.  Several  quarts  of  tar  may  be  tapped  from 
the  chamber  daily. 

The  gas-holder  serves  merely  to  regulate  the  pro- 
duction of  gas.  The  pipes  leading  to  the  engine  should 
be  cleaned  several  times  each  month,  in  order  to  re- 
move the  thin  layer  of  tar  which  is  deposited  within 
them. 

There  are  many  kinds  of  lignite,  and  the  gas-genera- 
tor should  be  constructed  to  meet  the  peculiar  require- 
ments of  the  variety  employed.  The  layer  of  fuel 
should  be  such  in  thickness  that  the  gas  as  it  emerges 
from  the  generator  has  a  temperature  of  about  77 
degrees  F.  This  is  the  temperature  of  the  gas  which 
leaves  the  scrubber  in  the  case  of  anthracite-generators. 
If  the  lignite  contains  much  water,  the  greater  part  is 
retained  in  the  washer  by  the  gas  in  the  form  of  drops. 
Sometimes  the  water  drips  through  the  grate  of  the 
generator.  Lignite-generators  may  also  be  operated 
with  peat,  and  even  with  town  refuse,  with  slight  modi- 


1 9o    GAS-ENGINES    AND    PRODUCERS 

fications.  The  consumption  per  horse-power  per  hour 
is  3.3  pounds  of  lignite  containing  2,400  calories 
(9,424.9  B.  T.  U.).  In  order  to  generate  the  same 
power  with  a  boiler  and  steam-engine,  8.8  pounds  would 
be  required.  An  engine  driven  unloaded  with  fuel 
furnished  by  a  lignite-generator  will  consume  50  per 
cent,  of  the  weight  of  the  fuel  required  at  full  load. 
This  depends  upon  the  proportion  of  water  contained 
in  the  lignite  and  on  losses  of  heat  by  radiation  from  the 
generator.  In  street-gas  engines  running  without  load, 
the  absorption  is  20  per  cent.,  in  anthracite-generators 
40  per  cent,  of  the  consumption  at  full  load. 

Passing  now  to  the  utilization  of  wood,  of  which 
something  has  already  been  said  in  Chapter  XI,  two 
entirely  distinct  processes  are  successfully  employed  in 
apparatus  of  the  Riche  type,  these  processes  depending 
upon  the  form  of  the  wood  used — whether,  in  other 
words,  the  wood  be  consumed  in  the  form  of  sticks  or 
blocks  or  in  the  form  of  chips,  sawdust,  bark,  and  the 
like,  all  of  them  the  wastes  of  factories  in  which  wood 
is  used. 

Distilling -Producers. — If  the  wood  consists  of  logs, 
it  is  burnt  in  a  generator  comprising  a  fire-box  and  a 
distilling  retort.  The  fire-box  is  charged  with  ordinary 
coal  which  serves  to  heat  the  retort  to  redness.  The 
wood  is  discharged  through  the  top  of  the  retort,  and 
the  gas,  produced  by  the  distillation,  escapes  through 
the  bottom  and  passes  to  the  washing  apparatus.  The 
base  of  the  retort  is  heated  to  about  1,652  degrees  F., 
while  at  the  top  this  temperature  is  reduced  to  752  de- 


or  THE 
UNIVERSITY 

OF 


DISTILLING-PRODUCERS 

•  • 

grees  F.     The  wood  thus  treated  is  transformed  into 
charcoal,  which  is  a  by-product  of  some  value. 

The  lower  part  of  this  cast  retort  (Fig.  87)  is  lined 
with   charcoal,    the    residue   of   previous   distillations. 


FIG.  87. — Rich£  distilling-producer. 

The  wood  which  is  introduced  in  the  upper  part  of 
the  retort  is  distilled  in  the  chamber.  The  retort  is 
held  by  its  own  weight  in  a  socket  on  the  foot,  which 
socket  is  lined  with  a  special  refractory  cement,  made 
of  silicate,  asbestos  forming  the  joint.  The  products 


1 92    GAS-ENGINES    AND    PRODUCERS 

of  combustion,  issuing  from  the  furnace,  pass  by  way 
of  the  flue  to  the  lower  part  of  the  casing,  and  raise 
the  temperature  of  the  retort  and  the  charcoal  it  con- 
tains to  that  of  a  cherry  red  (1,652  degrees  F.).  These 
products  of  combustion  then  float  to  the  upper  part  of 
the  casing  and  heat  the  top  of  the  retort  to  a  temperature 
of  about  752  degrees  F.,  in  which  part  the  wood  or  the 
wooden  waste  to  be  distilled  is  enclosed.  Thence  the 
products  of  combustion  pass  through  a  horizontal  flue, 
provided  with  a  damper,  into  a  collecting  flue  by  which 
they  are  led  to  the  smoke-stack.  The  products  of  distil- 
lation formed  in  the  chamber,  having  no  outlet  at  the 
top  of  the  retort,  must  traverse  the  zone  filled  with  in- 
candescent carbon.  The  condensible  products  are  con- 
ducted as  permanent  gases  (carbonic-acid  gas  in  the 
state  of  carbon  monoxide)  and  are  collected  in  the  re- 
ceptacle, after  having  passed  the  funnel  and  the  bell  of 
the  purifying  apparatus. 

A  gas-furnace  is  formed  by  grouping  in  a  single  mass 
of  masonry  a  certain  number  of  elements  of  the  kind 
just  described.  It  is  essential  that  the  retorts  should  be 
vertically  placed,  that  they  be  made  only  of  cast  metal 
and  not  of  refractory  clay,  and,  finally,  that  their  diam- 
eter be  not  much  more  -than  10  inches,  which  size 
has  been  found  most  expedient  in  practice.  The  gas 
collected  in  the  bell  or  in  one  or  more  of  the  receptacles 
passes  into  the  gasometer  and  then  into  the  service  pipes. 
If  2.2  pounds  of  wood  be  distilled  by  burning  in  the 
furnace  f  of  a  pound  of  coal  of  average  quality  or  2.2 
pounds  of  wood  (either  sawdust  or  waste),  24.5  to  28 


WOOD-PRODUCERS  193 

cubic  feet  of  gas  will  be  generated  having  a  thermal 
value  of  3,000  to  3,300  calories  per  cubic  meter  (11,904 
to  13,094  B.  T.  U.  per  35.31  cubic  feet),  and  a  residue 
44  pounds  of  charcoal  will  be  left. 

In  practice  only  the  wood  of  commerce  containing  in 
the  green  state  20  to  40  per  cent,  of  water,  depending 
upon  the  variety,  is  used.  Hornbeam  contains  the  least 
water  (18  per  cent),  while  elmwood  and  spruce  con- 
tain the  most  (44  to  45  per  cent). 

The  blast  apparatus  of  the  generator  being  started, 
the  gas  is  supplied  under  pressure.  By  reason  of  its 
permanent  composition  and  its  richness,  it  is  an  excel- 
lent substitute  for  street-gas  in  incandescent  lighting, 
a  good  furnace  fuel  reducing  agent. 

Producers  Using  Wood  Waste,  Sawdust,  and  the 
Like. — If  waste  wood  in  the  form  of  shavings,  sawdust, 
straw,  bark,  and  the  like,  should  be  employed,  a  still 
higher  efficiency  is  obtained  with  self-reducing  genera- 
tors of  the  Riche  type. 

Combustion-Generators. — In  combustion-generators 
(Fig.  88)  the  fuel  is  burnt  and  not  distilled.  The  gen- 
erator comprises  two  distinct  elements.  The  first  is  the 
generator  proper,  in  which  the  combustion  takes  place. 
Upon  it  is  placed  a  hopper  or  fuel  supply  box.  The 
second  element  is  the  reducer,  in  which  by  an  independ- 
ent process  the  reduction  of  the  carbonic-acid  gas,  the 
dissociation  of  the  steam,  and  the  transformation  of  the 
hydrocarbons  takes  place.  The  generator  is  provided 
at  its  base  with  a  grate  having  oblique  bars  in  tiers, 
which  grate  is  furnished  with  a  channel  in  which  the 


194    GAS-ENGINES    AND    PRODUCERS 

water  for  the  generation  of  hydrogen  flows.  On  a  level 
with  this  grate,  at  the  opposite  side,  is  a  flue  com- 
municating with  the  reduction  column  of  coke.  The 
incandescent  zone  of  the  generator  should  not  extend 
above  the  level  of  the  grate.  Instead  of  passing  through 
the  layers  of  fresh  fuel  and  out  by  way  of  the  top,  the 
gas  generated  flows  directly  into  the  reduction  column 
where  it  heats  the  coke  to  incandescence.  The  high 
temperature  to  which  the  coke  is  subjected,  coupled 
with  the  injection  of  air,  effects  useful  reactions.  This 


FIG.  88. — Riche  combustion-producer. 

additional  air,  however,  is  not  used  if  the  fuel  is  free 
from  all  products  of  distillation. 

Experience  has  shown  that  gas  of  1,000  to  1,100  cal- 
ories per  cubic  meter  (3,968  to  4,365  B.  T.  U.  per  35.31 
cubic  feet),  which  heat  content  is  necessary  to  develop 
one  horse-power  per  hour,  can  be  obtained  with  3.96 
pounds  of  wood  in  the  form  of  shavings  and  sawdust 
containing  30  per  cent,  of  water.  The  corresponding 
quantity  of  coke  consumed  in  the  reduction  column  is 


INVERTED    COMBUSTION 

insignificant,  and  may  be  placed  at  about  0.112  pounds 
per  horse-power  per  hour. 

It  has  been  proven  in  actual  practice  that,  both  in 
the  distilling  and  combustion  types  of  apparatus,  the 
wood,  either  in  the  green  state  or  in  the  form  of  saw- 
mill waste,  may  contain  as  much  as  60  per  cent,  of 
water.  Either  of  the  two  systems  can  be  operated  under 
pressure  with  an  air-blast,  in  which  case  a  gas-holder 
and  bell  must  be  employed.  The  gas  as  it  passes  from 
the  generator  to  the  gas-holder  is  conducted  through  a 
cooler  and  washer  and  through  a  moss  filter,  which 
removes  traces  of  the  products  that  may  have  escaped 
the  distillation. 

Inverted  Combustion.— With  a  few  exceptions  the 
pressure-generators  which  have  been  described,  as  well 
as  suction  gas-producers  which  will  be  later  discussed, 
are  fed  with  anthracite  coal  or  with  coke.  They  cannot 
be  operated  with  moderately  soft  or  bituminous  coal. 
For  this  reason  they  limit  the  employment  of  producer- 
gas  engines.  Manufacturers  have  long  sought  genera- 
tors in  which  any  fuel  whatever  can  be  consumed. 

Among  the  producers  which  seem  to  overcome  the 
objections  cited  to  a  certain  degree,  are  those  which  are 
based  on  the  principle  of  inverted  combustion.  These 
apparatus  embody  the  ideas  of  Ebelmen,  the  products 
of  distillation  being  decomposed  by  passing  them  over 
layers  of  incandescent  fuel. 

Many  writers  place  in  the  class  of  inverted  combus- 
tion producers,  apparatus  of  the  Riche,  Thwaite,  and 
Duff  type,  in  which  this  idea  is  also  carried  out.  Riche 


FIG.  89. — Deschamps  inverted-combustion  producer. 
196 


INVERTED-COMBUSTION 


197 


employs  an  independent  incandescent  mass  to  reduce 
the  products  of  distillation  of  another  mass.  Thwaite 
employs  two  vessels  which  serve  alternately  as  distilling 


FIG.  90. — Fange-Chavanon  inverted-combustion  producer. 

retorts  and  reducing  columns.  Duff  draws  in  the  prod- 
ucts of  distillation  for  the  purpose  of  blowing  them 
under  the  fire.  All  these  generators  can  hardly  be  said 
to  be  of  the  inverted  combustion  type. 


198    GAS-ENGINES    AND    PRODUCERS 

The  generators  of  Deschamps  (Fig.  89)  and  of 
Fange  and  Chavanon  (Fig.  90),  on  the  other  hand,  are 
producers  in  which  the  combustion  is  really  inverted, 
and  which  are  worked  continuously.  The  air  enters  at 
the  upper  part  of  the  retort,  passes  through  the  entire 
mass  of  fuel,  carrying  with  it  the  distilled  volatile  prod- 
ucts, and  when  the  mixture  reaches  the  incandescent 
zone,  chemical  reactions  occur  that  result  in  the  pro- 
duction of  a  gas  entirely  free  from  tar  and  other  im- 
purities. 


CHAPTER  XIII 

SUCTION  GAS-PRODUCERS 

THE  high  cost  and  the  complicated  nature  of  the 
pressure  gas-generators  which  have  just  been  discussed 
have  led  manufacturers  to  attempt  in  some  other  way 
the  generation  .of  producer-gas  intended  for  operating 
motors. 

Several  inventors,  among  whom  we  will  mention 
Benier  and  A.  Taylor  (in  France),  made  some  praise- 
worthy although  not  immediately  very  successful  at- 
tempts to  simplify  the  manufacture  of  producer-gas. 

Advantages. —  In  these  systems  the  suction  occa- 
sioned by  the  motor  itself  has  taken  the  place  of  a  forced 
draft,  produced  in  the  generator  by  an  air-injector  or  a 
fan,  so  that  the  gas,  instead  of  being  stored  under  pres- 
sure in  a  gas-holder,  is  kept  in  the  apparatus  under  a 
pressure  below  that  of  the  atmosphere. 

As  the  device  for  producing  a  draft  by  means  of 
boiler  pressure  or  of  a  fan,  and  the  gas-holder,  are  dis- 
pensed with,  the  result  is  a  saving,  first  in  the  cost  of 
installation,  consumption,  and  floor  space.  Further- 
more, the  cooler  and  washer  are  supplanted  by  a  single 
scrubber. 

Manufacturers  have  succeeded  in  devising  apparatus 

remarkable  for  the  simplicity  of  the  processes  employed 

199 


200    GAS-ENGINES    AND    PRODUCERS 

and  yielding  economical  results  which  would  never  be 
obtained  with  pressure-generators  employing  gas-hold- 
ers and  boilers,  considering  that  the  boiler  alone  calls 
for  a  consumption  of  from  15  to  30  per  cent,  of  the  total 
amount  of  coal  used  for  making  the  gas. 

The  best  results  obtained  by  the  author  with  pressure 
gas-producers  have  indicated  a  consumption  of  not 
much  less  than  i  to  1%  pounds  of  anthracite  per  horse- 
power per  hour  at  the  motor,  while  with  suction-gen- 
erators, under  similar  conditions  and  with  the  same 
grade  of  fuel,  he  has  repeatedly  found  a  consumption 
of  from  T9Q-  pounds  per  effective  horse-power  per  hour. 
In  either  case,  the  gas  obtained  developed  between 
1,100  and  1,300  calories  (4,365  and  5,158  B.  T.  U. 
per  35.31  cubic  feet)  if  produced  from  anthracite  yield- 
ing from  7,500  to  8,000  calories  (29,763  to  31,746- 
B.  T.  U.)  per  2.2  pounds. 

The  suction  apparatus  will  also  work  very  well  with 
inferior  coal  containing  up  to  6  to  8  per  cent,  of  volatile 
matter  and  from  8  to  10  per  cent,  of  ash.  This  great 
advantage  added  to  all  the  others  explains  the  favorable 
reception  which  European  manufacturers  at  once  gave 
to  suction-producers.  The  petroleum  engine  itself  will 
find  a  serious  competitor  in  the  new  system. 

As  regards  the  possibility  of  employing  suction  gas- 
generators  with  respect  to  the  somewhat  peculiar  prop- 
erties of  the  fuel,  it  may  be  said  at  the  outset  that  coke 
from  gas  works  yielding  from  6,000  to  6,500  calories 
(22,911  to  24,995  B.  T.  U.)  and  also  charcoal  are  per- 
fectly available. 


QUALITIES    OF    FUEL  201 

,  § 

One  horse-power  per  hour  is  obtained  with  a  con- 
sumption of  i.i  to  1.3  pounds  of  coke. 

Blast-furnace  coke  may  be  used  in  case  of  need,  but 
its  employment  is  not  to  be  recommended  on  account  of 
the  sulphides  it  contains,  which  sulphides,  being  car- 
ried along  by  the  gas,  are  liable  to  form  sulphuric  acid 
with  the  steam,  the  corrosive  action  of  which  would 
soon  destroy  the  cylinder  and  other  important  parts  of 
the  engine. 

Qualities  of  Fuel.— Anthracite  coal  is,  upon  the 
whole,  so  far  the  best  available  fuel  for  generators. 
However,  it  should  possess  certain  qualities  which  will 
now  be  briefly  indicated. 

In  suction  gas-generators,  above  all,  it  is  important 
that  no  harmful  resistance  should  be  opposed  to  the 
passage  of  the  air  and  of  the  gas  produced.  It  is  there- 
fore necessary  to  employ  coal  of  a  size  that  will  an- 
swer the  foregoing  condition,  without  being  too  expen- 
sive. 

The  size  of  the  pieces,  to  a  certain  extent,  determines 
the  price;  and  with  coal  of  the  same  properties,  pieces 
i.i  to  2  inches  may  cost  1.4  of  the  price  for  the  ordinary 
size  of  0.59  to  0.98  inches,  which  is  very  well  adapted 
for  gas-generators.  This  is  the  size  of  a  hazel-nut. 

Moreover,  it  will  be  advisable  to  select  the  dryest 
coals,  containing  a  minimum  of  volatile  matter  and  hav- 
ing no  tendency  to  coke  or  to  cohere,  in  order  that  the 
volatilized  products  may  not  by  distillation  obstruct  the 
interstices  through  which  the  gases  must  pass.  For  the 
same  reason  coal  which  breaks  up  and  becomes  pulver- 


202    GAS-ENGINES    AND    PRODUCERS 

ized  under  the  action  of  the  fire  is  not  to  be  recom- 
mended. The  coal  should  also  be  such  as  to  avoid  the 
formation  of  arches  which  would  interfere  with  the 
proper  settling  of  the  fuel  during  its  combustion.  It 
may  be  stated  as  a  rule  that,  with  coal  that  does  not  co- 
here, the  content  of  volatile  matter  should  not  exceed 
5  to  8  per  cent. 

Coal  which  contains  more  than  10  to  15  per  cent, 
of  ash  should  not  be  used,  for  the  reason  that  it  chokes 
up  and  obstructs  generators  in  which  the  dropping  and 
discharge  of  the  ashes  is  done  automatically,  a  fact 
which  should  not  pass  unnoticed.  The  furnace  cannot 
be  cleaned  safely  with  a  fire  of  this  kind,  where  com- 
bustion takes  place  in  an  enclosed  space,  without  hin- 
dering the  production  of  gas.  Here  again  a  point  may 
be  raised  very  much  in  favor  of  suction  gas-producers. 
In  a  good  generator,  the  ash-pit  can  be  cleaned  and  the 
fire  stoked  without  interrupting  the  liberation  of  the 
gas  drawn  in  and  without  appreciably  impairing  the 
quality  of  the  gas.  These  considerations  are  of  im- 
portance so  far  as  the  gas-generator  itself  is  concerned. 
Other  conditions  which  should  be  noticed  affect  the 
engine  fed  by  the  generator,  the  grade  of  coal  used,  and 
the  purification  of  the  gas  obtained  from  it. 

Unless  special  chemical  cleaners  and  purifiers  are 
employed,  thereby  complicating  the.  plant,  the  coal 
utilized  should  yield  as  little  tar  as  possible  during  dis- 
tillation; for  the  tendency  of  the  tar  to  choke  up  the 
pipes  and  to  clog  the  valves  is  one  of  the  chief  causes  of 
defective  operation  of  producer-gas  engines. 


QUALITIES    OF    FUEL  203 

• 

Tar  changes  the  proper  composition  of  the  explosive 
mixture.  When  it  catches  fire  in  the  cylinder  it  causes 
premature  ignition,  which  is  so  dangerous  in  large  en- 
gines. 

From  what  has  been  said  in  the  foregoing,  it  follows 
that,  in  the  present  state  of  the  art,  the  satisfactory 
operation  of  gas-generators  depends  no  longer  on  the 
use  of  pure  anthracite,  such  as  Pennsylvania  coal  in 
America  and  Welsh  coal  in  England,  containing  an 
amount  of  carbon  as  high  as  90  to  94  per  cent,  and  hav- 
ing a  thermal  value  of  33,529  B..T.  U.  On  the  con- 
trary, good  dry  coal  yielding  from  29,763  to  31,746 
B.  T.  U.  is  quite  suitable  for  the  generation  of  pro- 
ducer-gas. 

A  final,  practical  advantage  which  speaks  in  favor  of 
a  generator  and  motor  plant  as  compared  with  a  steam- 
engine,  is  the  small  amount  of  water  required.  Apart 
from  the  water  used  for  cooling  the  engine,  which  may 
be  used  over  and  over  again  if  cooled,  any  water, 
whether  it  forms  scale  or  deposits,  may  be  employed  for 
cooling  and  washing  the  gas  in  the  scrubber. 

According  to  the  author's  personal  experience,  an 
average  of  3.3  gallons  of  water  per  effective  horse- 
power per  hour  is  sufficient  for  this  purpose.  This  is 
about  one-half  of  the  amount  required  by  a  non-con- 
densing slide-valve  engine  of  from  15  to  30  horse- 
power. The  difference  in  the  consumption  of  water  is 
quite  important  in  city  plants,  where  water  is  rather 
expensive  as  a  rule. 

General    Arrangement. — A   suction    gas-generator 


204    GAS-ENGINES    AND    PRODUCERS     ' 

plant  of  the  character  we  have  been  discussing  is  shown 
in  Fig.  91. 

The  apparatus  A  is  the  generator  proper,  in  which 
combustion  takes  place.  The  gas  produced  passes  into 
the  apparatus  B  through  a  series  of  tubes,  to  be  con- 
veyed to  the  washer  C.  In  the  apparatus  JB,  which  is 
the  vaporizer,  the  water  admitted  at  the  top  under  at- 
mospheric pressure  is  vaporized  by  contact  with  a  series 
of  tubes,  heated  by  the  gas  coming  from  the  generator. 


FIG.  91.— Engine  and  suction  gas-producer. 

The  steam,  together  with  air,  is  drawn  into  the  lower 
part  of  the  generator  to  support  combustion.  This  vapor- 
izer is  provided  with  an  overflow  for  the  outlet  of, the 
water  which  has  not  been  vaporized.  The  producer- 
gas  pipe  which  leads  from  the  vaporizer  to  the  washer 
has  a  branch  Z),  for  the  temporary  escape  to  the  atmos- 
phere of  the  gas  produced  before  and  after  the  opera- 
tion of  the  engine.  In  the  washer,  as  the  drawing 
shows,  the  gas  enters  at  the  bottom  and  leaves  at  the  top 
to  pass  to  the  gas  expansion-chamber  E  and  thence  to 
the  motor.  The  gas  thus  passes  through  the  body  of 


GENERAL   ARRANGEMENT          205 

t 

coke  in  the  opposite  direction  to  the  wash  water,  which 
then  flows  to  the  waste-pipe.  The  coke  and  the  water 
free  the  gas  not  only  from  the  dust  carried  along,  but 
from  the  ammonia  and  other  impurities  contained  in 
the  gas. 

When  firing  the  generator,  a  small  hand  ventilator 
G  is  used  for  blowing  in  air  to  fan  the  fire.  The  gas 
obtained  at  first,  being  unsuitable  for  combustion,  is 
allowed  to  escape  through  the  branch  D.  After  in- 
jecting air  for  about  10  to  15  minutes,  the  engine  can 
be  started  after  closing  the  branch  D.  The  suction  of 
the  engine  itself  will  then  gradually  bring  about  the 
proper  conditions  for  its  regular  running,  and  after  a 
quarter  of  an  hour  or  half  an  hour  the  gas  is  rich 
enough  to  run  the  engine  under  a  full  load. 

The  apparatus  just  described  is  the  original  type, 
upon  which  many  improvements  have  been  made  for 
the  purpose  of  securing  a  uniform  gas  production  and 
of  diminishing  the  interval  of  time  elapsing  between 
the  firing  of  the  generator  and  the  running  of  the  en- 
gine under  a  full  load. 

Each  of  the  elements  of  this  apparatus — to  wit,  the 
generator,  vaporizer,  superheater,  and  washer — 4iave 
been  modified  and  improved  more  or  less  successfully 
by  the  manufacturers;  and  in  order  that  the  reader  may 
perceive  the  merits  and  the  drawbacks  of  the  various 
arrangements  adopted,  the  most  important  ones  will  be 
separately  discussed. 

Generator. — With  respect  to  the  general  arrangement 
of  parts,  generators  may  be  divided  into  two  classes : 


206    GAS-ENGINES    AND    PRODUCERS 


First. — Generators  with  internal  vaporizers,  such  as. 
the  Otto  Deutz  and  Wiedenfeld  generators. 


FIG.  92. — Old  type  of  Winterthur  producer. 

Second. — Generators  with  external  vaporizers,  such 
as  the  Taylor,  Bollinckx,  Pintsch,  Kinderlen,  Benz, 
Wiedenfeld,  Hille,  and  Goebels  generators. 


CONSTRUCTION  OF  GENERATOR  207 

,     • 

Cylindrical  Body. — The  generator  consists  essen- 
tially of  a  mantle  made  of  sheet-iron  or  cast-iron  and 
containing  a  refractory  lining  which  forms  a  retort,  a 
grate,  and  an  ash-pit.  In  the  small  size  apparatus  the 
cast-iron  mantle  is  often  used,  whereas  in  large  sizes 
the  mantle  is  made  of  riveted  sheet-iron  so  as  to  reduce 
its  weight  and  its  cost.  In  the  latter  case  the  linings 
are  securely  riveted  or  bolted. 

The  Winterthur  generator  (Figs.  92  and  93),  the 
Taylor  generator  (Fig.  94),  and  the  Benz  generator 
(Fig.  97),  are  made  of  cast-iron;  the  Wiedenfeld  gen- 
erator (Fig.  95),  the  Pintsch  generator  (Fig.  96),  are 
made  of  sheet-iron;  the  Bollinckx  (Fig.  98)  is  made 
partly  of  sheet-iron  and  partly  of  cast-iron. 

The  different  parts  of  a  generator,  if  made  of  sheet- 
iron,  are  held  together  by  means  of  angle-irons  form- 
ing yokes,  and  a  sheet  of  asbestos  is  interposed.  If  the 
parts  are  made  of  cast-iron,  they  are  connected  after  the 
manner  of  pipe-joints  and  packed  with  compressed  as- 
bestos. This  latter  way  of  assembling  the  parts  pre- 
sents the  advantage  of  allowing  them  to  be  dismem- 
bered readily.  Therefore,  it  allows  the  several  parts  to 
expand  freely  and  facilitates  the  securing  of  tight  joints. 
This  last  consideration  is  exceedingly  important,  par- 
ticularly for  the  joints  which  are  beyond  the  zone  in 
which  the  distillation  of  the  fuel  takes  place.  Any  en- 
trance of  air  through  these  joints  would  necessarily  im- 
pair the  quality  of  the  gas,  either  by  mingling  there- 
with, or  by  combustion.  The  air  so  admitted  would 
also  be  liable  to  form  an  explosive  mixture  which  might 


FIG.  93.— New  type  of  Winterthur  producer. 
208 


! 

OH 

1 

PQ 

o^ 

o 

— 


210 


SUCTION    GAS-PRODUCERS 


211 


become  ignited  in  case  of  a  premature  ignition  of  the 
cylinder  charge  during  suction  or  through  some  other 
cause. 

Refractory  Lining. — The  interior  lining  of  the  gen- 
erator should  be  made  of  refractory  clay  of  the  best 


FIG.  99. — Lencauchez  producer. 

quality.  It  would  seem  advisable,  in  order  to  facilitate 
repairs,  to  employ  retorts  made  of  pieces  held  together 
instead  of  retorts  made  of  a  single  piece.  In  the  first 
case  the  assembling  should  preferably  be  made  by 
means  of  refractory  cement,  and  the  inner  surface 


212    GAS-ENGINES    AND    PRODUCERS 

should  be  covered  with  a  coating  so  as  to  form  a  prac- 
tically continuous  stone  surface. 

Some  manufacturers,  in  order  to  allow  for  the  re- 


FIG.  100. — Goebels  producer. 

newal  of  the  part  most  liable  to  be  burnt,  employ  at  the 
bottom  of  the  tank  a  refractory  moulded  ring  (Len- 
cauchez,  Fig.  99). 

It  is  always  advisable  to  place  between  the  shell  or 


GENERATOR    DESIGN 


213 


mantle  of  the  generator  and  the  refractory  lining  a 
layer  of  a  material  which  is  a  bad  conductor  of  heat  as, 


FIG.  1 01. — Pierson  producer. 

for  instance,  asbestos  or  sand,  in  order  to  avoid  as  much 
as  possible  loss  of  heat  due  to  external  radiation  (Fig. 
100). 


214    GAS-ENGINES    AND    PRODUCERS 

Grate  and  Support  for  the  Lining.— These  parts, 
owing  to  their  contact  with  the  ashes  and  the  hot  em- 
bers, are  liable  to  deteriorate  rapidly.  It  is  therefore 
indispensable  that  they  should  be  removable  and  easily 
accessible,  so  that  they  may  be  renewed  in  case  of  need. 
From  this  point  of  view,  grates  composed  of  inde- 
pendent bars  would  appear  to  be  preferable.  The 
clearance  between  the  bars  depends,  of  course,  on  the 
kind  of  ashes  resulting  from  the  different  grades  of 
fuel.  It  is  advisable  to  design  the  grate  so  that  the  free 
passage  for  the  air  is  about  60  to  70  per  cent,  of  the 
total  surface. 

In  generators  having  a  cup-shaped  ash-pit,  contain- 
ing water  (Fig.  95),  the  grate  and  the  base  of  the  re- 
tort are  less  liable  to  burn  than  in  apparatus  having  dry 
ash-pits.  Certain  apparatus,  such  as  those  of  Lencau- 
chez  (Fig.  99),  Pierson  (Fig.  101),  and  Taylor  (Fig. 
94) ,  have  no  grates ;  the  fuel  is  held  in  the  retort  by  the 
ashes,  which  form  a  cone  resting  on  a  sheet-iron  base, 
easy  of  access  for  cleaning  and  from  which  the  fuel 
slides  down  gradually. 

The  Pierson  generator  (Fig.  101)  is  provided  with 
a  poker  comprising  a  central  fork,  which  is  worked 
with  a  lever,  in  order  to  stir  the  fire  from  below  with- 
out entirely  extinguishing  the  cone  of  ashes. 

In  some  apparatus  in  which  a  grate  is  used  (Fig.  92), 
a  space  is  left  between  the  grate  and  the  support  of  the 
retort.  This  arrangement  has  the  merit  of  allowing 
only  finely  divided  and  completely  burnt  ashes  to  pass 
to  the  ash-pit.  Moreover,  a  large  surface  grate  can  be 


GRATES 


2I5 


employed,  thus  facilitating  the  passage  of  the  mixture 
of  air  and  steam. 

The  space  above  mentioned  is  provided  with  a  clean- 


FIG.  102. — Kiderlen  producer. 

ing-door  through  which  cinder  and  slag  may  be  re- 
moved. 

In  other  apparatus  the  grate  rests  either  on  the  sup- 
port of  the  refractory  lining,  as  in  the  old  type  invented 


2i 6    GAS-ENGINES    AND    PRODUCERS 

by  Wiedenfeld  (Fig.  95),  or  upon  a  projection  em- 
bedded in  the  lining,  as,  for  instance,  in  the  Kiderlen 
(Fig.  102)  and  Pintsch  generators  (Fig.  96). 

In  the  Riche  apparatus  (Fig.  103)  there  is,  besides 
the  ordinary  grate,  a  grate  with  tiers  on  which  the  fuel 


FIG.  103. — Riche  combustion -producer. 

spreads.  This  grate  consists  of  wide,  hollow  bars  con- 
taining water.  It  should  be  noted  that  the  apparatus  is 
of  the  blower  type. 

An  interesting  arrangement  is  found  in  Benier's  gen- 
erator (Fig.  104).  This  consists  of  a  grate  formed  of 
projections  cast  around  a  cylinder  which  can  be  turned 
about  its  axis.  The  finely  divided  ashes  which  are  re- 


BENIER'S    GRATE 


217 


tained  in  the  spaces  between  these  projections  are  thus 
carried  into  the  ash-pit,  and  those  which  adhere  to  the 
metal  are  scraped  away  by  a  metallic  comb  fastened  to 


x>$$^^S^^ 

FIG.  104. — Benier  producer. 

the  lower  part  of  the  apparatus.    The  "  Phoenix  "  gen- 
erator   (Fig.    105)    is   fitted  with   a   grate   having   a 
mechanical  cleaning  device,  worked  by  a  lever  from  the 
outside. 
Ash-Pit. — The  ash-pits  are  exposed  to  the  destructive 


FIG.  105. — Phoenix  producer. 

218 


ASH-PITS 


219 


effects  of  heat  and  moisture,  and  should  preferably  be 
constructed  of  cast-iron,  since  sheet-steel  is  liable  to 
corrode  quickly. 


FIG.  106. — Otto  Deutz  producer. 

In  most  apparatus  the  ash-pit  is  hermetically  sealed, 
and  the  air  for  supporting  combustion  enters  below  the 


220    GAS-ENGINES    AND    PRODUCERS 

grate  through  a  pipe  leading  from  the  heater  or  the 
vaporizer.  This  arrangement  seems  best  adapted  to 
prevent  the  leakage  of  gas  which  tends  to  take  place  by 
reaction  after  each  suction  stroke  of  the  engine. 

Ash-pits  formed  as  water-cups,  such  as  the  Deutz 
(Fig.  1 06),  the  Wiedenfeld  (Fig.  95),  and  the  Bol- 
linckx  (Fig.  98),  are  fed  by  the  overflow  from  the 
vaporizer.  These  ash-pits  are  themselves  provided 
with  an  overflow  consisting  of  a  siphon-tube  forming  a 
water-seal. 

Besides  providing  protection  to  the  grate  and  other 
parts  by  this  sheet  of  water,  a  larger  proportion  of  the 
heat  radiated  from  the  furnace  is  utilized  for  the  pro- 
duction of  steam  which  contributes  to  enrich  the  gas. 
The  doors  of  the  ash-pits  and  their  fittings  are  likewise 
exposed  to  a  rapid  deterioration. 

For  this  reason  these  parts  should  be  very  strongly 
made,  either  of  cast-iron  or  cast-steel.  Furthermore, 
they  should,  at  joint  surfaces,  be  connected  in  an  air- 
tight manner,  which  may  be  attained  by  carefully  fin- 
ishing the  engaging  surfaces  of  the  frame  and  the  door 
proper,  or  by  cutting  a  dovetail  groove  in  one  of  the 
sides  of  the  frame  which  is  packed  with  asbestos  and 
adapted  to  receive  a  sharp  edged  rib  on  the  other  part. 

The  pintles  of  the  hinges  should  also  be  carefully 
adjusted  so  that  the  joint  members  of  the  door  shall  re- 
main true.  Hinges  with  horizontal  axes  seem  to  be 
preferable  in  this  respect  to  those  having  vertical  axes. 
As  a  means  of  closing  the  door,  the  arrangement  here 
shown  (Fig.  107)  seems  to  assure  a  proper  engagement 


FIRE-BOX    DOORS 


221 


of  the  joint  surfaces.  It  consists  of  a  yoke  which  strad- 
dles the  door,  and  which,  on  the  one  hand,  swings  about 
the  hinge,  and  on  the  other  hand  engages  a  movable 
hoop.  A  screw,  fastened  to  the  yoke,  serves  to  tighten 
the  door  by  pressure  on  its  center.  This  screw  can  also 
be  fastened  to  the  end  of  the  yoke  (Fig.  108). 

It  is  very  advantageous  to  provide  in  each  door  a 
hole  closed  by  an  air-tight  plug,  so  that  in  case  of 


FIGS.  107-108. — Fire-box  doors. 

need  a  tool  may  be  introduced  for  cleaning  the  grate. 
In  this  manner  the  grate  may  be  cleaned  without 
opening  doors  and  without  causing  a  harmful  entrance 
of  air. 

The  door  of  the  furnace,  particularly,  should  be  pro- 
vided with  an  iron  counter-plate  held  by  hinged  bolts 
(Fig.  109)  ;  or,  better  still,  this  door^should  be  so  con- 
structed that  it  can  be  lined  with  refractory  material  to 
protect  it  against  the  radiated  heat  of  the  fire. 

Charging-Box. — Like  the  other  parts  of  the  genera- 
tor the  construction  of  which  has  been  discussed  above, 
the  charging-box  should  be  absolutely  air-tight. 


222    GAS-ENGINES    AND    PRODUCERS 

On  account  of  their  greater  security,  preference 
should  be  given  to  double  closure  devices,  which  form 
a  sort  of  preliminary  chamber,  owing  to  which  the  fill- 
ing of  the  generator  is  made  in  two  operations.  The 
first  operation  consists  in  filling  the  preliminary  cham- 
ber after  opening  the  outer  door.  Upon  closing  this 
outer  door,  the  second  operation  is  performed,  which 
consists  in  moving  the  inner  door  so  as  to  cause  the  fuel 
in  the  preliminary  chamber  to  drop  into  the  generator. 


FIG.  109. — Door  with  refractory  lining. 

Stress  has  been  laid  on  the  greater  safety  of  this  type  of 
charging-box  for  the  reason  that,  with  devices  having  a 
single  charging-door,  a  sudden  gust  of  air  may  rush 
in  at  the  time  of  charging  the  furnace,  and  bring  about 
an  explosion  very  dangerous  to  the  workman  entrusted 
with  stoking  the  furnace. 

The  closure  is  generally  simply  a  removable  cover, 
or  may  be  a  lid  swinging  about  a  hinge  having  a  hori- 
zontal or  vertical  axis. 

As  regards  the  inner  door,  which  is  of  great  im- 
portance, in  order  to  insure  an  air-tight  joint,  there  are 
three  chief  types  of  closure: 


TYPES    OF    CLOSURE  223 

1.  The  Lift-Valve. 

2.  The  Slide-Valve. 

3.  The  Cock. 

The  Lift-Valve. — The  lift-valve  is  formed  by  a  disk 
of  conical  or  spherical  shape  moved  up  and  down  by 
means  of  a  lever  having  a  counter-weight  for  adjust- 
ment. The  valve  is  used  in  the  Winterthur  (Fig.  92) 
and  Bollinckx  (Fig.  98)  generators. 

This  device  serves  as  an  automatic  closure  and  insures 
a  tight  joint  irrespective  of  wear.  Moreover,  it  presents 
the  advantage  that,  at  the  moment  of  opening,  it  dis- 
tributes the  fuel  evenly  in  the  generator;  but  on  .the 
other  hand,  it  has  the  drawback  of  not  allowing  the 
fuel  to  be  examined  or  shaken  through  the  charging- 
box.  In  apparatus  provided  with  this  kind  of  valve,  it 
is  therefore  advisable  to  furnish  the  upper  part  of  the 
generator  with  agitating  holes  closed  by  an  air-tight 
slide. 

Slide-Valve. — The  slide-valve  closure  consists  of  a 
smooth-finished  metallic  plate  movable  below  the 
charging-box  proper.  Operated  as  it  is  from  the  out- 
side, it  is  evident  that  the  slightest  play,  the  wearing  of 
the  pivot,  or  the  weight  of  the  charge,  will  form  spaces 
between  the  plate  and  its  seat  through  which  air  may 
rush  in. 

Furthermore,  the  manipulation  of  the  slide-valve 
may  be  interfered  with  if  too  much  fuel  is  put  in  the 
generator. 

The  valve  or  damper  may  move  parallel  to  itself  or 
swing  about  the  operating  axis.  The  Taylor  apparatus 


224    GAS-ENGINES    AND    PRODUCERS. 

(Fig.  94)  and  the  Benier  apparatus  (Fig.  104)  are 
provided  with  such  valves. 

The  Pintsch  generator  (Fig.  96)  is  provided  with  a 
device  which,  properly  speaking,  is  not  a  damper,  but 
which  consists  of  two  boxes  movable  about  a  vertical 
axis  and  arranged  to  be  displaced  alternately  above  the 
shaft  to  effect  the  charging.  This  system  effects  only 
a  single  closure,  but  explosions  are  scarcely  to  be  feared 
with  an  apparatus  of  this  kind,  owing  to  the  consider- 
able height  of  fuel  contained  between  the  charging 
opening  and  the  gas-producing  zone. 

Cock. — The  cock  is  applied  particularly  in  the  mod- 
ern apparatus  of  the  Otto  Deutz  Co.  (Fig.  106)  and 
the  Pierson  generator  (Fig.  101).  It  consists  of  a  large 
cast-iron  cone,  having  an  operating  handle  and  an 
opening.  The  cone  moves  in  a  sleeve  formed  by  the 
charging-box. 

This  arrangement  appears  to  be  preferable  to  the 
others  on  account  of  its  simplicity  and  of  the  ease  with 
which  it  can  be  taken  apart  for  cleaning.  Moreover, 
the  fuel  can  be  poked  directly  through  the  feed-hopper. 
In  apparatus  provided  with  a  cock,  it  is  advisable  to 
place  on  the  outside  cover  a  mica  pane  through  which 
the  condition  of  the  fuel  may  be  examined  without 
danger. 

Feed-Hopper. — Below  the  charging-box  is  arranged, 
as  a  rule,  a  hopper  tapered  conically  downward.  This 
part  of  the  generator  should  serve  only  as  a  storage 
chamber  for  fuel.  It  can  therefore  be  made  of  cast- 
iron,  and  has  the  advantage  of  being  removable,  easily 


CONNECTION    OF    PARTS  225 

9 

replaced,  and  of  allowing  ready  access  to  the  retort  for 
the  purposes  of  examination  and  repair. 

The  annular  space  surrounding  this  feed-hopper  gen- 
erally forms  a  chamber  for  receiving  the  gas  produced, 
as  in  the  Winterthur  (Fig.  92),  the  Bollinckx  (Fig. 
98),  and  the  Taylor  apparatus  (Fig.  99). 

In  generators  having  an  internal  vaporizing-tank, 
this  tank  itself  serves  as  a  feed-hopper,  which  is  the 
case  in  the  Deutz  apparatus  (Fig.  106)  and  Wieden- 
feld  generator  (Fig.  95). 

Connection  of  Parts. — In  order  to  facilitate  the 
thorough  cleaning  of  the  retort,  preference  is  given  to 
removable  charging-boxes  and  feed-hoppers.  These 
are  features  of  apparatus  of  the  Bollinckx  type  (Fig. 
98),  in  which  the  charging-box  is  secured  to  the  gen- 
erator by  means  of  its  yoke  and  by  catches  provided 
with  knobs,  and  also  of  apparatus  of  the  Winterthur 
kind  (Fig.  92),  having  a  charging-box  pivoted  about 
a  vertical  axis,  or  apparatus  of  the  Duplex  type  (Fig. 
no),  in  which  the  charging-box  can  swing  about  a 
horizontal  hinge. 

Air  Supply. — We  have  seen  that,  when  starting  the 
generator,  the  gas  is  produced  with  the  aid  of  a  fan. 
This  fan  may  be  operated  mechanically,  but  is  generally 
operated  by  hand. 

It  is  customary  to  convey  the  air-blast  through  a  pipe 
leading  to  the  ash-pit,  as  in  the  Winterthur  apparatus 
(Fig.  92).  Often,  however,  the  air  supply  pipe  is  di- 
rectly branched  on  that  which  leads  from  the  vapor- 
izer to  the  ash-pit,  as  in  the  Deutz  apparatus  (Fig. 


226    GAS-ENGINES    AND    PRODUCERS 

106).  In  this  case  a  set  of  valves  or  dampers  permits 
the  disconnection  of  the  fan  or  its  connection  with  the 
ash-pit. 

In  some  apparatus  an  air  inlet  is  provided  imme- 
diately adjacent  to  the  ash-pit.  This  arrangement  is 
faulty  for  the  reason  that  it  gives  rise  to  gaseous  emana- 
tions which  take  place  by  reaction  after  each  suction 


FIG.  no. — Duplex  charging-hopper. 


stroke  of  the  engine.  Furthermore,  it  is  advisable  that 
the  air  supplied  below  the  ash-pit  be  as  hot  as  possible. 
For  this  reason  the  employment  of  preheaters  is  desir- 
able. The  dry  air  forced  in  by  the  fan  stimulates  com- 
bustion, and  the  hot  gas  produced  and  mixed  with 
smoke  escapes  through  a  separate  flue,  generally  ar- 
ranged beyond  the  vaporizer  and  serving  as  a  chimney. 
This  chimney  should  in  all  cases  be  extended  to  the 
outside  of  the  building,  and  should  never  terminate  in 


AIR    SUPPLY 


227 


a  brick  chimney  or  similar  smoke-flue.     The  direct 
escape  of  such  gas  and  smoke  through  a  telescopic 


FIG.  in. — Bollinckx  flue 
and  scrubber. 


FIG.  112. — Winterthur  flue 
and  air-reheater. 


chimney  above  the  charging-box  has  been  generally 
abandoned  in  modern  structures. 


228    GAS-ENGINES    AND    PRODUCERS 


The  escape-pipe  mentioned,  being  branched  on  the 
gas-pipe  leading  to  the  engine,  should  be  capable  of 
disconnection  when  desired,  by  a  thoroughly  tight  sys- 
tem of  closure.  For  this  purpose,  some  employ  a  simple 


FIG.  113.— Otto  Deutz  flue. 


FIG.  114. — Benz  flue. 


cock  (Bollinckx,  Fig.  in),  a  three-way  cock,  a  set  of 
cocks,  or,  still  better,  a  double  valve,  as  in  the  Winter- 
thur  apparatus  (Fig.  112)  and  the  Deutz  apparatus 
(Fig.  113).  A  double  seated  valve  is  also  used,  as  is 
the  case  in  the  Benz  generator  (Fig.  114). 


VAPORIZERS  229 

Vaporizer-Preheaters. — As  has  been  stated  before, 
there  are  vaporizers  internal  or  external,  relatively  to 
the  generator. 

Internal  Vaporizers. — The  Deutz  apparatus  (Fig. 
1 06),  for  example,  consists  of  an  annular  cast-iron  tank 
mounted  above  the  retort  of  the  generator. 

The  hot  gases  given  off  by  the  burning  fuel  travel 
around  this  tank  and  vaporize  the  water  which  it  con- 
tains. The  air  drawn  in  by  the  suction  of  the  engine 
enters  through  an  opening  located  above  the  tank, 
travels  over  the  surface  of  the  water  which  is  being 
vaporized,  and  thus  laden  with  steam  passes  to  the 
ash-pit. 

The  tank  in  question  is  supplied  with  water  by  means 
of  a  cock  having  a  sight  feed,  located  on  the  outside, 
and  the  level  is  kept  constant  by  means  of  an  overflow 
tube  leading  to  the  ash-pit.  It  is  well  to  bend  this  tube 
and  to  place  a  funnel  on  its  lower  member.  The 
amount  of  overflow  may  thus  be  regulated. 

These  vaporizers  are  simple  and  take  up  little  room; 
but  they  are  open  to  the  apparently  well-founded  objec- 
tion that  they  heat  up  slowly  and  require  a  considerable 
time  to  produce  the  steam  necessary  to  enrich  the  gas, 
this  being  due  to  the  relatively  large  mass  of  cast-iron 
and  the  amount  of  water  contained  therein. 

The  Pierson  vaporizer  (Fig.  101)  and  the  Chavanon 
vaporizer  (Fig.  115)  both  consist  of  an  annular  tank 
forming  the  base  of  the  generator.  Steam  is  formed 
near  the  outlet  of  the  ashes,  which,  as  has  been  described 
above,  leads  to  the  outer  air.  The  development  of 


23o    GAS-ENGINES    AND    PRODUCERS 

steam  is  regulated  by  mechanical  means  controlled  by 
the  suction  of  the  engine. 
External  Vaporizers. — External  vaporizers  are  gen- 


FIG.  115. — Chavanon  producer. 


erally  formed  by  a  cylinder  with  partitions  constituting 
two  series  of  chambers.     In  one  of  these  the  hot  gases 


VAPORIZERS 


231 


from  the  generator  travel,  and  in  the  others  the  water  to 
be  vaporized  is  contained. 

Tubular  Vaporizers. — Different  types  of  tubular 
vaporizers  are  manufactured.  The  vaporizer  with  a 
series  of  tubes,  as  in  Taylor's  apparatus  (Fig.  116), 


FIG.  116. — Taylor  vaporizer. 


FIG.  117. — Deutz  vaporizer. 


Deutz's  old  model  (Fig.  117),  or  with  single  tube  like 
Pintsch's  generator  (Fig.  118),  is  formed  by  three  com- 
partments separated  by  two  tube  sheets  or  by  plates 
which  are  connected  by  tubes. 

In  some  cases  the  gases  pass  within  the  tubes,  while 
the  water  to  be  vaporized  surrounds  them;  as  in  the 


232    GAS-ENGINES    AND    PRODUCERS 

Pintsch  apparatus  (Fig.  118),  and  Taylor  apparatus 
(Fig.  116),  Benz  (Fig.  119),  and  Koerting  genera- 
tors (Fig.  120). 

In  other  cases,  the  water  lies  inside  and  the  gas  out- 


FIG.  118. — Pintsch  vaporizer  and  scrubber. 

side.  In  this  latter  case,  a  longitudinal  baffle  is  em- 
plpyed  to  compel  the  gases  to  heat  the  tubes  in  their 
whole  length,  as  in  the  Deutz  producer  (Fig.  1 17) .  In 
a  general  way  it  may  be  said  that  such  a  series  of  tubes 


VAPORIZERS 


233 


presents  the  disadvantage  of  becoming  clogged  up 
rapidly  by  the  deposit  of  lime  salts  contained  in  water. 
If  the  set  of  tubes  consists  of  fire-tubes,  the  deposit 
will  form  on  the  outer  surface,  that  is,  on  a  portion  not 
accessible  for  cleaning.  From  this  point  of  view, 


FIG.  119. — Benz  vaporizer. 


FIG.  120. — Koerting  vaporizer. 


water-tubes  are  preferable,  as  they  allow  the  deposit  or 
scale  to  be  removed  through  the  tubular  heads  or  plates. 
On  the  other  hand,  such  water-tubes  have  the  draw- 
back that  their  exterior  surfaces  are  readily  covered 
with  pitch  and  soot.  The  tubular  vaporizers  of  the 


234    GAS-ENGINES    AND    PRODUCERS 

Field  type  (Bollinckx,  Fig.  98)  are  composed  of  a 
single  sheet-iron  tube  or  shell,  in  which  the  tubes  are 
arranged,  dipping  into  a  chamber  through  which  the 
hot  gases  pass.  This  arrangement  insures  a  rapid  pro- 
duction of  steam,  but  the  Field  tubes  are  even  more 
liable  than  the  others  to  become  covered  with  deposits. 

It  will  be  seen  that  these  types  of  vaporizers  should 
all  present  the  following  features:  easy  access,  small 
quantity  of  the  body  of  water  undergoing  vaporization, 
and  large  heating  surface  with  small  volume. 

The  use  of  copper  or  brass  tubes  should  be  strictly 
avoided,  as  they  would  be  quickly  corroded  by  the 
action  of  the  ammonia  and  hydrogen  sulphide  con- 
tained in  the  gas. 

Partition  Vaporizers. — Partition  vaporizers  com- 
prise a  cylindrical  shell,  generally  made  of  cast-iron 
and  having  a  double  wall  in  which  the  water  to  be 
vaporized  circulates.  The  gas  coming  from  the  gen- 
erator passes  into  the  central  portion,  where  it  comes  in 
contact  with  a  hollow  baffle,  also  containing  water 
(Wiedenfeld,  Fig.  121).  Vaporizers  of  this  kind  are 
strong,  simple,  and  easily  cleaned. 

Operation  of  the  Vaporizers. — The  general  pur- 
pose of  vaporizers,  whatever  their  construction  may  be, 
is  to  produce  steam  under  atmospheric  pressure,  by 
utilizing  the  heat  of  the  generator  gases  immediately 
after  their  production,  or,  as  in  the  Chavanon  system, 
by  utilizing  the  heat  radiated  from  the  furnace. 

The  air  drawn  by  the  engine  through  the  generator 
generally  passes  through  the  vaporizers  and  becomes 


VAPORIZERS 


235 


laden  with  a  certain  amount  of  steam  which  it  carries 
along.  The  amount  thus  taken  up  depends  chiefly  upon 
the  temperature  and  the  amount  of  gases  coming  from 
the  generator,  so  that  the  greater  the  amount  drawn  into 


FIG.  121. — Wiedenfeld  vaporizer. 

the  engine,  the  more  energetic  will  the  vaporization  be, 
and  the  richer  the  gas  will  become.  It  will  be  under- 
stood that  when  a  generator  is  working  at  its  maximum 
production,  the  interior  temperature  is  highest  and 
most  favorable  to  the  decomposition  of  the  largest 
amount  of  steam. 


236    GAS-ENGINES    AND    PRODUCERS 

It  follows  that  with  the  very  simple  vaporizers  which 
have  been  reviewed,  a  practically  automatic  regulation 
is  obtained.  However,  some  manufacturers  have 
deemed  it  advisable  to  regulate  the  amount  of  steam 
more  accurately,  and  to  make  it  exactly  proportionate 
to  the  power  developed  by  the  motor.  Thus  in  the 
Winterthur  gas-producer  (Figs.  92  and  1 12)  the  manu- 
facturers have  omitted  the  vaporizer  proper,  and  use 
instead  an  air-heater  and  a  super-heater  for  air  and 
steam. 

The  heater  is  formed  by  a  cast-iron  box  having  two 
compartments,  through  one  of  which  the  hot  gases  from 
the  generator  pass,  while  in  the  other  the  air  intended 
to  support  combustion  travels.  At  the  inlet  of  the 
super-heater  a  pipe  terminates,  which  feeds,  drop  by 
drop,  water  supplied  by  a  feed  device  to  be  described 
presently.  This  water  is  vaporized  immediately  upon 
contact  with  the  wall  of  the  super-heater  and  is  carried 
along  with  the  air  contained  in  it. 

The  super-heater  comprises  a  hollow  ring-shaped 
cast-iron  piece  arranged  in  the  chamber  of  the  genera- 
tor, in  which  the  gases  are  developed,  and  is  thus  heated 
to  a  high  temperature.  The  mixture  of  air  and  steam 
circulates  in  this  super-heater  before  traveling  to  the 
ash-pit. 

The  feeder  of  the  Winterthur  gas-generator  (Fig. 
122)  is  composed  of  a  receptacle  having  the  shape  of  a 
tank  or  basin  containing  water  and  located  below  a 
closed  cylindrical  box.  In  this  box  a  piston  moves, 
which  is  provided  at  its  lower  end  with  a  needle-valve. 


FEEDERS 


237 


The  upper  portion  of  the  box  communicates  with  the 
gas-suction  pipe  through  a  small  tube.  At  each  suction 
stroke  of  the  engine,  according  to  the  force  of  the  suc- 
tion, the  needle-valve  piston  rises  more  or  less  and  thus 
allows  a  variable  amount  of  water  to  pass. 


FIG.  122. — Winterthur  feeders. 

This  apparatus — and  all  those  based  on  the  same 
principle — presents  the  advantage  of  proportioning  the 
amount  of  water  to  the  work  of  the  engine;  but  in  view 
of  its  rather  sensitive  operation  it  must  be  kept  in  per- 
fect repair  and  carefully  watched.  Obviously,  should 
the  water  contain  impurities,  the  needle-valve  will  bind 


238    GAS-ENGINES    AND    PRODUCERS 

or  the  orifices  will  be  obstructed,  and  thus  the  feeding 
of  the  water  will  be  interrupted.  This  \vill  not  only  re- 
sult in  the  production  of  a  poorer  gas,  but  will  lead  to 
greater  wear  of  the  grates,  which  in  this  case  are  not 
sufficiently  cooled  by  the  introduction  of  steam. 


FIG.  123. — Hille  producer. 

Air-Heaters. — The  preliminary  heating  of  the  air 
appears  to  be  of  great  utility  for  keeping  up  a  good  fire. 
This  heating  is  very  easily  accomplished,  and  is  gen- 
erally effected  by  utilizing  a  portion  of  the  waste  heat 
of  the  gases,  a  procedure  which  also  has  the  advantage 
of  cooling  the  gases  before  they  pass  through  the  wash- 
ing apparatus. 


DUST-COLLECTORS 


239 


The  heating  of  the  air  for  supporting  combustion 
takes  place  either  before  the  addition  of  steam  (Hille's 
generator,  Fig.  123),  or  after  the  mixture  as  in  Wieden- 
feld's  apparatus  (Fig.  95).  In  the  first  case,  the  air 
passes  through  a  sheet-iron  shell  concentric  with  the 
basin  of  the  generator,  is  there  heated  by  the  radiated 
heat,  and  is  conveyed  to  the  ash-pit  by  a  tube  into  which 
leads  the  steam-supply  pipe  extended  from  the  vapor- 
izer. In  the  second  type  of  heater,  the  mixture  of  air 
and  steam  is  super-heated  during  its  passage  through  an 
annular  piece  arranged  in  the  ash-pit  of  the  generator. 


FIG.  124. — Benz  dust -collector. 

Dust-Collectors.  —  Dust-collectors  are  generally 
placed  between  the  generator  and  the  scrubber  or 
washer.  They  may  be  formed  of  baffle-board  arrange- 
ments against  which  the  gases  laden  with  dust  impinge, 
causing  the  dust  to  be  thrown  down  into  a  box  provided 
with  a  cleaning  opening  (Benz,  Fig.  124,  and  Pintsch, 
Fig.  118). 

Some  collectors  are  formed  either  by  the  vaporizer 
itself,  terminating  at  its  base  in  a  tube  which  dips  into 
water  and  forms  a  water-seal,  as  in  the  Wiedenfeld  gen- 
erator (Fig.  121),  or  by  a  water-chamber  into  which 
the  gas-supply  tube  slightly  dips  (Bollinckx,  Fig.  in). 


240    GAS-ENGINES    AND    PRODUCERS 

With  this  arrangement,  the  gas  will  bubble  through  the 
water  and  will  be  partly  freed  of  the  dust  suspended  in 
it.  These  water-chambers  are  generally  fed  by  the 
overflow  from  the  spray  of  the  scrubber.  There  is  thus 
produced  a  continuous  circulation  by  which  the  dust, 
in  the  form  of  slime,  is  carried  toward  the  waste-pipe  or 
sewer. 

Cooler,  Washer,  Scrubber.— Some  manufacturers 
cool  the  gas  in  a  tower  with  water  circulation.  Most 
manufacturers,  however,  simply  cool  the  gas  in  the 
washer  or  scrubber.  This  apparatus  comprises  a  cy- 
lindrical body  of  sheet-iron  or  cast-iron  formed  of  two 
compartments  separated  by  a  wooden  or  iron  grate  or 
perforated  partition.  The  upper  compartment  up  to 
a  certain  level  contains  either  coke,  glass  balls,  stones, 
pieces  of  wood,  and  the  like.  The  top  of  the  compart- 
ment is  provided  with  a  water  supply  in  the  nature  of 
a  sprinkler  or  spray  nozzle.  The  lower  compartment 
of  the  scrubber  serves  to  collect  the  wash-water  which 
has  passed  through  the  substance  filling  the  tower.  An 
overflow  in  the  shape  of  a  siphon,  provided  with  a  water 
seal,  carries  the  water  to  the  waste-pipe  either  directly 
or  after  it  has  first  passed  through  the  dust  collector. 

The  gas  drawn  in  enters  the  washer  in  the  lower  com- 
partment either  above  the  water  level  (Deutz,  Fig. 
125;  Winterthur,  Fig.  126),  or  through  an'  elbow 
which  dips  slightly  into  the  water  (Benz,  Fig.  127; 
Fichet  and  Heurtey  producer,  Fig.  128). 

The  gas  passes  through  the  grate  or  partition  which 
supports  the  material  filling  the  tower,  and  travels 


COOLER,    WASHER,    SCRUBBER      241 

§ 

through  the  interstices  in  a  direction  opposite  to  that  of 
the  water  falling  from  the  top.  Under  these  conditions, 
the  gas  is  cooled,  gives  up  the  ammonia  and  the  dust 


FIG.  126. — Winterthur  scrubber. 


FIG.  125. — Otto  Deutz  scrubber. 


which  it  may  still  contain  in  suspension,  and  is  conveyed 
to  the  engine  either  directly  or  after  passing  through 
certain  purifiers.  Care  should  be  taken  to  place  the 


242    GAS-ENGINES    AND    PRODUCERS 

pieces  of  most  regular  shape  along  the  walls,  so  that 
the  unevenness  of  their  surfaces  may  not  form  upward 


FIG.  127. — Benz  scrubber. 

channels  along  the  shell,  through  which  channels  the 
gas  could  pass  without  meeting  the  wash-water. 

The  material  most  commonly  employed  in  washers  is 
coke  in  pieces  of  from  2^  to  3^  inches  in  size.  This 
material  is  cheap  and  is  very  well  suited  for  retaining 


WASHERS 


243 


the  impurities  of  the  gas.  The  largest  pieces  of  coke 
should  be  placed  at  the  bottom  of  the  washer,  and 
smaller  pieces  should  form  at  the  top  a  layer  from  6  to 


FIG.  128. — Fichet-Heurtey  scrubber.  FIG.  129. — Scrubber-doors. 

8  inches  deep.  In  this  manner  the  water  is  distributed 
more  evenly  and  the  gas  is  more  thoroughly  washed. 
Blast-furnace  coke  is  best  suited  for  this  washing,  as  it 
is  more  porous  and  less  brittle  than  gas-works  coke.  It 


244    GAS-ENGINES    AND    PRODUCERS 

is  advisable  to  put  a  baffle-board  in  front  of  the  gas  out- 
let to  reduce  the  carrying  along  of  water  in  the  con- 
duits. 

The  tower  of  the  washer  should  be  provided  with 
three  openings  having  air-tight  closures,  easily  fastened 
by  screws  (Fig.  129).  One  of  the  openings  is  located 
in  the  lower  compartment,  slightly  above  the  water 
level,  to  allow  the  deposits  to  be  removed  and  to  per- 
mit the  cleaning  of  the  orifice  of  the  gas-supply  tube, 
which  is  particularly  liable  to  be  obstructed.  The  sec- 
ond opening  is  placed  above  the  grating  which  sup- 
ports the  filtering  material.  The  third  opening  is  pro- 
vided on  the  top  of  the  apparatus  to  permit  the  exam- 
ination and  cleaning  of  the  water  feed  device  and  the 
gas  outlet  without  the  necessity  of  taking  the  lid  of  the 
washer  apart,  the  joint  of  which  is  kept  tight  with  diffi- 
culty. The  two  openings  last  mentioned  also  serve  for 
introducing  and  removing  the  filtering  material. 

Purifying  Apparatus. — In  some  cases,  wrhere  it  is 
necessary  to  have  very  clean  gas  or  where  coal  is  em- 
ployed which  is  softer  than  anthracite  coal,  and  which 
therefore  produces  an  appreciable  amount  of  tar,  sup- 
plementary purifying  means  must  be  employed.  The 
apparatus  for  this  purpose  may,  like  the  washers,  be 
based  upon  a  physical  action  or  upon  a  chemical  action. 
The  physical  action  has  for  its  purpose  chiefly  to  re- 
tain the  pitch  and  the  dust  which  may  have  passed 
through  the  washer. 

This  is  accomplished  by  means  of  sawdust  or  wood 
shavings  arranged  in  a  thin  layer  and  capable  of  filter- 


PURIFIERS 


245 


ing  the  gas  without  opposing  too  great  a  resistance  to 
its  passage.  These  materials  are  spread  on  one  or  more 
shelves  superposed  to  form  successive  compartments  in 
a  box  closed  in  an  air-tight  manner  by  an  ordinary  lid 
or  a  water  seal  cover  (Pintsch,  Fig.  130;  Fichet  and 
Heurtey,  Fig.  131).  It  may  be  well  to  point  out  that 
the  presence  of  the  water  carried  along  will,  in  the  end, 
destroy  the  efficiency  of  the  precipitated  materials, 


FIG.  130. — Pintsch  purifier. 

because  they  swell  up  and  cease  to  be  permeable  to 
the  gas.  These  materials  must  therefore  be  renewed 
rather  frequently.  To  obviate  this  drawback,  vegetable 
moss  may  be  employed,  which  is  much  less  affected  by 
moisture  than  most  filters  and  keeps  its  spongy  condi- 
tion for  a  long  time. 

The  chemical  action  has  for  its  chief  object  to  rid 
the  gas  of  the  carbonic  acid  and  the  hydrogen  sulphide 
which  certain  fuels  give  off  in  appreciable  amounts. 


246    GAS-ENGINES    AND    PRODUCERS 

The  purifying  material,  in  this  case,  is  formed  either 
by  a  mixture  of  hydrate  of  lime  and  natural  iron  oxide, 
or  by  the  so-called  Laming  mass,  which  consists  of  iron 
sulphide,  slaked  lime,  and  sawdust,  which  last  serves 


FIG.  131. — Fichet-Heurtey  purifier. 

the  purpose  of  rendering  the  material  looser  and  more 
permeable  to  the  gas.  The  Laming  mass  as  well  as 
other  purifying  materials  will  become  exhausted  in  the 
course  of  chemical  reactions.  It  can  be  regenerated 
merely  by  exposure  to  the  air. 


STORAGE    OF    GAS 


247 


Gas-Holders. — The  purifiers  by  themselves  consti- 
tute, to  a  certain  extent,  storage  chambers  for  the  gas 
before  it  is  supplied  to  the  engine;  but  in  plants  for  the 
generation  of  gas  without  purifiers  it  is  advisable  to 
provide  a  gas-holder  on  the  suction  conduit  near  the 
engine. 

In  order  to  save  floor  space  the  gas-holder  may  be 


FIG.  132. — Pintsch  regulating-bell. 

placed  in  the  basement.  Preferably  the  capacity  of 
the  holder  should  be  at  least  from  3  to  4  times  the  vol- 
ume of  the  engine-cylinder.  The  holder  should  also 
be  provided  with  a  drain-cock  and  with  a  hand-hole 
located  at  some  accessible  point,  so  that  the  slimes  and 
pitch  which  tend  to  accumulate  in  the  holder  can  be 
removed.  In  some  cases  the  gas-holder  is  formed  by  a 


248    GAS-ENGINES    AND    PRODUCERS 


small  regulating  bell,  the  function  of  which  is  to  in- 
sure a  uniform  pressure.  This  bell  is  emptied  during 
the  suction  period  and  is  filled  during  the  three  suc- 


FIG.  133. — Types  of  gas-driers. 

ceeding  periods  of  compression,  explosion,  and  exhaust 
(Pintsch,  Fig.  132). 

Drier. — Sometimes,  toward  the  end  of  a  producer- 
gas  pipe,  a  drier  is  located  for  the  purpose  of  keeping 
back  the  water  carried  along,  the  drier  being  similar  to 
that  employed  in  steam  conduits.  It  will,  of  course,  be 

m 


FIG.  134. — Elbow  with  closure. 

understood  that  such  driers  are  useful  only  in  plants 
having  no  purifiers  (Fig.  133).  The  employment  of 
the  drier  is  advisable  to  prevent  the  entrance  of  moist 
gas  into  the  cylinder  and  the  condensation  of  moisture 
on  the  electric  igniter. 
Pipes. — The  pipes  connecting  the  several  parts  of 


PIPE    CONNECTIONS  249 

f  *  • 

a  gas-producing  plant  should  be  disposed  with  partic- 
ular care  to  insure  tightness  and  cleanliness.  It  should 
be  borne  in  mind  that  the  gas  is  under  a  pressure  below 
that  of  the  atmosphere,  and  that  the  least  leakage  will 
cause  the  entrance  of  air,  which  will  impair  the  qual- 
ity of  the  gas.  The  greatest  care  should  therefore  be 
taken  in  fitting  the  joints.  These  joints  are  numerous, 
because  there  are  joints  wherever  tubes  are  connected 
with  each  other  and  with  the  apparatus.  Further- 
more, all  elbows  should  be  provided  with  covers  held 
in  place  by  a  yoke  and  compression  screw,  this  being 
done  for  the  purpose  of  providing  for  the  introduction 
of  a  brush  or  other  implement  to  remove  the  dust  and 
pitch  (Fig.  134). 

For  conduits  of  small  diameter  the  elbows  with  cov- 
ers may  be  replaced  with  T  connections,  or  connections 
provided  with  plugs. 

Gas  piping  in  the  immediate  neighborhood  of  the 
cock  for  admitting  gas  to  the  motor  should  be  provided 
with  a  conduit  of  proper  diameter  leading  to  the  open 
air  and  serving  to  clean  the  apparatus  and  to  fill  them, 
during  the  operation  of  the  fan,  with  gas  suitable  for 
combustion.  This  conduit  should  be  provided  with  a 
stop-cock.  Test-cocks  for  the  gas  should  be  placed  on 
the  piping  immediately  beyond  the  vaporizers,  the 
scrubber,  and  near  the  engine. 

It  will  also  be  well  to  provide  water-pressure  gages 
before  and  after  the  scrubber  to  enable  the  attendant 
to  ascertain  the  vacuum  in  the  conduits  and  to  adjust 
the  running  of  the  apparatus. 


GAS-ENGINES    AND    PRODUCERS 

Purifying-Brush. — As  an  additional  precaution 
against  the  carrying  of  tar  to  the  engine,  metallic 
brushes  are  often  employed,  these  brushes  being  spiral 
in  form  and  enclosed  in  a  cast-iron  box  interposed  in 
the  gas-supply  pipe  immediately  after  the  engine.  The 


FIG.  135. — Metal  purifying-brush. 

gas  will  be  broken  up  into  streams  by  the  obstacles 
formed  by  these  brushes  and  will  be  freed  of  the  sus- 
pended tar  (Fig.  135).  These  brushes  should  be  care- 
fully cleaned  at  regular  intervals.  The  best  way  of 
doing  this  is  to  drop  them  into  kerosene  or  some  other 
suitable  solvent. 


SUCTION    GAS-PRODUCERS  251 

• 

CONDITIONS  OF  PERFECT  OPERATION 
OF    GAS-PRODUCERS 

These  conditions  depend  upon  the  workmanship  or 
upon  the  system  of  the  plant,  on  the  care  with  which 
it  has  been  erected,  on  the  nature  of  the  fuel,  on 
the  condition  of  preservation  of  the  apparatus,  and 
upon  the  manner  in  which  the  .producers  have  been 
working. 

Workmanship  and  System. — The  workmanship 
itself,  which  term  is  meant  to  include  the  choice  of 
materials  and  the  way  they  have  been  worked,  presents 
no  difficulty.  The  producers  which  we  have  discussed 
are  very  simple  and  offer  absolutely  no  difficulties  in 
their  mechanical  execution.  As  regards  the  system, 
however,  especially  with  respect  to  the  relative  dimen- 
sions of  the  elements,  it  does  not  seem  so  far  that  it  is 
possible  to  indicate  any  principle  or  rule  capable  of 
a  rigid  general  application.  It  must  be  taken  into 
account  that  the  use  of  suction  gas-generators  has 
become  general  only  in  the  last  three  or  four  years; 
the  problem  has  therefore  scarcely  been  adequately 
solved.  However,  some  hints  may  be  given  on  this 
subject. 

Generator. — In  regard  to  the  generator,  it  is  pos- 
sible to  deduce  from  the  best  existing  plants  the  dimen- 
sions to  be  given  to  the  generator  relatively  to  those  of 
the  engine  to  be  supplied,  upon  the  assumption  that  the 
engine  is  single-acting  and  runs  at  a  normal  speed  of 


252    GAS-ENGINES    AND    PRODUCERS 

from  1 60  to  230  revolutions  per  minute.  The  essential 
portion  of  the  generator  which  contributes  to  the  pro- 
duction of  a  proper  gas  is  that  which  corresponds  with 
the  combustion  zone.  To  this  portion  a  cross-section  is 
given  varying  in  size  between  one-half  and  one-quarter 
of  the  surface  of  the  engine-piston,  sometimes  between 
one-half  and  nine-tenths  of  this  surface,  according  to 
the  nature  and  the  size  of  the  fuel  that  is  used.  With 
small  apparatus,  however,  ranging  from  5  to  15  horse- 
power, the  size  of  the  base  cannot  be  reduced  below  a 
certain  limit,  since  otherwise  the  sinking  of  the  fuel 
will  be  prevented.  This  danger  always  exists  in  small 
generators  and  renders  their  operation  rather  uncertain, 
such  uncertainty  being  also  due  to  the  influence  of  the 
walls.  It  is  to  be  noted  that  most  modern  generators  are 
rather  too  large  than  otherwise. 

Many  manufacturers  of  no  wide  experience  have 
been  led  to  make  their  apparatus  rather  large  so  as  to 
insure  a  more  plentiful  production  of  gas.  As  a  matter 
of  fact,  the  fire  in  such  apparatus  is  liable  to  be  extin- 
guished when  the  combustion  is  not  very  active.  If  the 
principles  of  the  formation  of  gas  in  suction-generators 
be  kept  in  mind,  it  is  evident  that  the  gas  developed  is 
the  richer  the  "  hotter  "  the  operation  of  the  apparatus. 
Such  operation  also  permits  the  decomposition  of  the 
hydrogen  and  carbon  monoxide. 

The  "  hot "  operation  of  a  generator  is  accomplished 
best  with  active  combustion;  and  since  this  is  a  function 
of  the  rapidity  with  which  the  air  is  fed,  it  obviously  is 
advantageous  to  reduce  the  area  of  the  air-passage  to  a 


VAPORIZER    AND    SCRUBBER 


253 


minimum  as  far  as  allowed  by  the  amount  of  fuel  to  be 
treated.  As  to  the  height  of  the  fuel  in  use  in  the  ap- 
paratus, this  varies  as  a  rule  between  4  and  5  times  the 
diameter  at  the  base. 

Vaporizer. — The  size  of  the  vaporizer  varies  ma- 
terially according  to  its  type.  No  hard-and-fast  rule 
can  therefore  be  adopted  for  determining  its  heating 
surface;  but  this  surface  should  in  all  cases  be  sufficient 
to  vaporize  under  atmospheric  pressure  from  .66  to  .83 
pounds  of  water  per  pound  of  anthracite  coal  consumed 
in  the  generator. 

Scrubber. — For  the  scrubbers,  the  following  dimen- 
sions may  be  deduced  from  constructions  now  used  by 
standard  manufacturers. 

The  volume  of  a  scrubber  is  generally  from  six  to 
eight  times  the  anthracite  capacity  of  the  generator.  A 
height  of  from  three  to  four  times  the  diameter  is  con- 
sidered sufficient  in  most  cases.  It  should  be  under- 
stood that  in  this  height  is  included  the  water-pan 
chamber  located  below  the  partition  or  grate,  and  the 
upper  chamber  through  which  the  gas  escapes.  The 
height  of  these  two  chambers  depends  necessarily  upon 
the  arrangement  used  for  leading  the  gas  to  the  lower 
portion  of  the  washer  and  for  the  distribution  of  wash- 
water  at  the  top. 

Assembling  the  Plant. — The  author  has  insisted 
strongly  on  the  necessity  of  having  all  the  apparatus 
and  pipe  connections  perfectly  tight.  In  order  to  as- 
certain if  there  is  any  leakage,  the  following  procedure 
may  be  adopted: 


254    GAS-ENGINES    AND    PRODUCERS 

When  starting  the  fire  by  means  of  wood,  straw,  or 
other  fuel  producing  smoke,  instead  of  allowing  this 
smoke  to  escape  through  the  flue  during  the  operation 
of  the  fan,  it  may  be  caused  to  escape  through  the  cock 
which  generally  admits  the  gas  to  the  motor,  the  cock 
being  opened  for  this  purpose.  The  damper  in  the  out- 
let flue  is  closed.  In  this  manner  the  smoke  will  fill  all 
the  apparatus  and  connecting  pipes  under  a  certain 
pressure  and  will  escape  through  any  cracks,  the  pres- 
ence of  wThich  will  thus  be  revealed. 

Another  test,  which  is  made  during  the  ordinary  op- 
eration of  the  generator,  consists  in  passing  a  lighted 
candle  along  the  joints ;  if  there  is  any  leakage,  this  will 
be  shown  by  a  deviation  of  the  flame  from  a  vertical 
position. 

Fuel. — We  have  discussed  the  subject  of  fuel  in  a 
preceding  chapter  (Chapter  XIII)  and  have  indicated 
the  conditions  to  be  fulfilled  by  low  grade  or  anthracite 
coal  best  adapted  for  use  in  suction  gas-generators.  It 
may  here  be  added  that  the  coal  used  in  the  generator 
should  be  as  dry  as  possible  and  in  pieces  of  from 
y2  inch  to  i  inch.  Very  small  pieces,  and  particularly 
coal  dust,  are  injurious  and  should  be  removed  by  pre- 
liminary screening  as  far  as  possible.  Screened  coal 
is  thrown  in  with  an  ordinary  grate  shovel. 

How  to  Keep  the  Plant  in  Good  Condition.— In 
regard  to  the  generator,  apart  from  the  cleaning  of  the 
grate  and  of  the  ash-pit,  which  may  be  done  during 
operation,  it  is  necessary  to  empty  the  apparatus  en- 
tirely once  a  week,  if  possible,  in  order  to  break  off  the 


MAINTENANCE  OF   PLANT 


255 


clinkers  adhering  to  the  retort.  These  clinkers  destroy 
the  refractory  lining,  form  rough  projections  interfer- 
ing with  the  downward  movement  of  the  fuel,  bring 
about  the  formation  of  arches,  and  reduce  the  effective 
area  of  the  retort.  At  the  time  of  this  cleaning,  tests 
are  also  made  as  to  the  tightness  of  the  doors  of  the 
combustion-chamber,  of  the  charging-boxes,  etc. 

The  vaporizer  should  be  cleaned  every  week  or  every 
other  week,  according  to  the  more  or  less  bituminous 
character  of  the  fuel  and  the  greater  or  smaller  content 
of  lime  in  the  water  used.  Lime  deposits  may  be 
eliminated,  or  the  salts  may  be  precipitated  in  the  form 
of  non-adhering  slimes,  by  introducing  regularly  a 
small  amount  of  caustic  postash  or  soda  into  the  feed- 
water.  If  the  deposits  or  incrustations  are  very  tena- 
cious, the  use  of  a  dilute  solution  of  hydrochloric  acid 
may  be  resorted  to.  Tar  which  may  adhere  to  the 
conduits,  pipes  or  gas  passages,  is  best  removed  while 
the  apparatus  is  still  hot,  or  a  solvent  may  be  employed, 
such  as  kerosene,  turpentine,  etc.  The  connections  be- 
tween the  vaporizer  and  the  scrubber  are  particularly 
liable  to  become  obstructed  by  the  accumulation  of  tar 
or  dust  carried  along  by  the  gas. 

It  is  advisable  to  examine  the  several  parts  of  the 
plant  once  or  twice  a  week  by  opening  the  covers  or  the 
cleaning-plugs. 

The  lower  compartment  of  the  washer  keeps  back 
the  greater  part  of  the  dust  which  has  not  been  retained 
in  collectors  or  boxes  provided  especially  for  this  pur- 
pose. The  dust  takes  the  form  of  slime,  and,  in  some 


256    GAS-ENGINES    AND    PRODUCERS 

arrangements  of  apparatus,  tends  to  clog  up  the  over- 
flow pipe,  thus  arresting  the  passage  of  *gas  and  causing 
the  engine  to  stop.  This  portion  of  the  washer  should 
be  thoroughly  cleaned  once  or  twice  a  month. 

If  very  hard  blast-furnace  coke  is  used  in  the  washer, 
it  may  be  kept  in  use  for  over  a  year  without  requiring 
removal.  In  order  to  free  the  purifying  materials  from 
dust  and  lime  sediments  carried  along  by  the  wash- 
water,  it  is  well  to  let  the  wash-water  flow  as  abundantly 
as  possible  for  about  a  half-hour  at  least  once  a  month. 
At  the  time  of  renewing  the  purifying  material  the 
precautions  indicated  in  the  section  dealing  with  these 
matters  should  be  observed,  and  care  should  be  taken 
to  have  shelves  or  gratings  on  which  the  material  is 
supported  in  layers  not  too  thick,  so  as  to  avoid  any 
resistance  to  the  passage  of  the  gas. 

In  a  general  way  it  is  advisable  to  test  the  drain- 
cocks  on  the  several  apparatus  daily,  and  to  keep  them 
in  perfect  condition.  If,  when  open,  one  of  these  cocks 
does  not  discharge  any  gas,  water,  or  steam,  a  wire 
should  be  introduced  into  the  bore  to  make  sure  it  is 
not  clogged  up. 

Care  of  the  Apparatus. — Each  producer-gas  plant 
will  require  special  instructions  for  running  it,  accord- 
ing to  the  system,  the  construction,  and  the  size  of  the 
plant.  Such  instructions  are  generally  furnished  by 
the  manufacturer.  However,  there  are  some  general 
rules  which  are  common  to  the  majority  of  suction  gas- 
producers,  and  these  will  here  be  enumerated. 

Starting  the  Fire  for  the  Gas  Generator. — This 


CARE    OF   THE    APPARATUS         257 

• 

operation  calls  for  the  presence  of  the  engineer  of  the 
plant  and  an  assistant.  The  proper  procedure  is  as  fol- 
lows : 

First:  Open  the  doors  of  the  furnace  and  of  the  ash- 
pit. Then  open  the  outlet  flue  and  make  sure  that  the 
grate  of  the  generator  is  clear  of  ashes  and  clinkers.  It 
should  also  be  seen  to  that  the  parts  of  the  charging-box 
work  well  and  that  the  joints  are  tight. 

Second:  Ascertain  whether  there  is  the  proper 
amount  of  water  in  the  vaporizer,  in  the  scrubber,  etc., 
and  that  the  feed  works  properly. 

Third:  Through  the  door  of  the  combustion-cham- 
ber introduce  straw,  wood  .shavings,  cotton  waste,  etc. ; 
light  them  and  fill  the  generator  with  dry  wood  up  to 
one-quarter  or  one-half  of  its  height;  then  add  a  few 
pailfuls  of  coal. 

Fourth:  Close  the  doors  of  the  ash-pit  and  of  the 
combustion-chamber  and  start  the  draft  by  means  of  the 
fan.  As  soon  as  the  draft  is  started,  it  must  be  kept  up 
without  interruption  until  the  engine  begins  to  run, 
which  may  be  ten  or  twenty  minutes  after  lighting 
the  fire. 

Fifth:  After  the  draft  has  been  continued  for  a  few 
minutes,  the  coal  becomes  sufficiently  incandescent  to 
start  the  production  of  gas,  which  may  be  ascertained 
by  trying  to  light  the  gas  at  the,  test-cock  near  the  gen- 
erator. Then  the  opening  in  the  outlet  flue  is  half 
closed  for  the  purpose  of  producing  pressure  in  the 
apparatus. 

Sixth :  Open  the  outlet  flue  adjacent  to  the  engine  for 


258    GAS-ENGINES    AND    PRODUCERS 

• 

the  purpose  of  purging  the  apparatus  and  the  conduits 
of  the  air  which  they  contain  until  the  gas  may  be 
lighted  at  the  test-cock  placed  near  the  motor. 

Seventh:  Adjust  the  normal  outflow  of  wash-water 
for  the  scrubber. 

Eighth:  As  soon  as  the  gas  burns  continuously  at  the 
test-cock  with  an  orange-colored  flame  the  engine  may 
be  started. 

The  gas  at  first  burns  with  a  blue  flame;  this  color 
indicates  that  it  contains  a  certain  amount  of  air.  The 
opening  of  the  test-cock  should  be  so  regulated  as  to 
reduce  the  outlet  pressure  of  the  gas  sufficiently  to  pre- 
vent the  flame  from  going  out.  During  the  production 
of  the  draft,  as  well  as  during  the  ordinary  running  of 
the  plant,  the  filling  of  the  apparatus  with  fuel  should 
be  done  with  care  to  prevent  explosions  of  gas  due  to  the 
entrance  of  air.  Particular  care  should  be  taken  never 
to  open  at  the  same  time  the  lid  of  the  charging-box  and 
the  device,  be  it  a  cock,  valve,  or  damper,  which  con- 
trols the  connection  of  the  charging-box  with  the  gen- 
erator. All  the  operations  which  have  been  mentioned 
above  should  be  carried  out  as  quickly  as  possible. 

STARTING   THE    ENGINE 

The  manner  of  starting  the  engine  depends  on  the 
type  of  the  engine  and  on  the  starting  device  with 
which  it  is  provided,  as  we  have  already  explained  in 
connection  with  engines  working  with  gas  from  city 
mains. 


STARTING    THE    ENGINE 


259 


It  is,  however,  important  for  the  production  of  a 
good  explosive  mixture  to  regulate  the  amount  of  air 
supplied  to  the  engine  according  to  the  quality  of  the 
gas  employed.  It  is  advisable  to  continue  the  operation 
of  the  fan  until  several  explosions  have  taken  place  in 
the  cylinder  and  the  engine  has  acquired  a  certain 
speed  so  as  to  be  able  to  draw  in  the  normal  amount 
of  gas. 

Naturally  the  gas-outlet  tube  near  the  admission- 
cock  should  be  closed  after  starting  the  engine,  as 
well  as  the  opening  in  the  outlet  flue  of  the  generator. 
When  the  motor  is  running  properly,  the  amount  of 
water  fed  to  the  vaporizer  and  overflowing  to  the  ash- 
pit is  properly  adjusted.  The  generator  is  then  filled 
up  to  the  level  indicated  by  the  manufacturer. 

Care  of  the  Generator  during  Operation. — As 
soon  as  the  apparatus  is  running  under  normal  con- 
ditions, it  presents  the  advantage  of  requiring  only  very 
slight  supervision  and  very  little  manual  tending.  The 
supervision  consists: 

First:  In  regulating  and  keeping  up  a  proper  feed 
of  water  to  the  vaporizer. 

Second:  In  seeing  to  it  that  in  apparatus  provided 
with  an  overflow  leading  to  the  ash-pit,  the  water 
should  flow  constantly  but  without  exceeding  the 
proper  amount. 

Third:  In  keeping  down  temperature  in  the  scrub- 
ber by  properly  regulating  the  feed  of  the  wash-water. 
This  apparatus  may  be  slightly  warm  at  its  lower  part, 
but  must  be  quite  cold  at  the  top. 


26o    GAS-ENGINES    AND    PRODUCERS 

The  manual  tending  to  be  done  is  limited  to  the  reg- 
ular filling  up  of  the  generator  with  fuel  and  to  the 
removal  of  ashes  and  clinkers.  The  charging  is  effected 
at  regular  intervals,  which,  according  to  the  various 
types  of  anthracite-generators,  vary  from  one  to  six 
hours.  Charging  the  apparatus  at  short  intervals  en- 
tails unnecessary  labor,  while  charging  at  too  long 
intervals  will  often  interfere  with  the  uniform  produc- 
tion of  the  gas. 

It  will  be  obvious  that  the  amount  of  fuel  introduced 
will  be  the  larger,  the  greater  the  intervals  between  two 
fillings.  This  fuel  is  cold  and  contains  between  its 
particles  a  certain  amount  of  air;  furthermore,  the  layer 
of  coal  which  covers  the  incandescent  zone  has  become 
relatively  thin.  The  excess  of  air  impoverishes  the  gas, 
and  the  fresh  fuel  lowers  the  temperature  of  the  mass 
undergoing  combustion,  so  that  again  the  gas  in  process 
of  formation  is  weakened.  Experience  seems  to  show 
that  as  a  rule  it  is  best  to  fill  up  the  generator  at  inter- 
vals of  from  two  to  three  hours,  according  to  the  work 
done  by  the  engine.  It  should  be  noted  that  the  level 
of  the  fuel  in  the  generator  should  not  sink  below  the 
bottom  of  the  feed-hopper. 

The  author  wishes  again  to  emphasize  that  in  order 
to  prevent  the  harmful  entrance  of  air,  the  charging 
operations  should  be  carried  out  as  quickly  as  possible; 
and  for  this  reason  the  fuel  should  be  introduced  not  by 
means  of  the  shovel,  but  by  means  of  a  pail,  scuttle,  or 
other  appropriate  receptacle. 

Care  should  be  taken  to  fill  the  charging  box  to  its 


STOPPAGES    AND    CLEANI 

i 

upper  edge  and  to  adjust  its  cover  accurately  before 
operating  the  device  which  closes  the  feed-hopper 
(valve,  cock). 

The  removal  of  the  ashes  and  clinkers  should  be  ac- 
complished as  infrequently  as  possible,  since  opening 
the  doors  of  the  ash-pit  and  of  the  combustion-chamber 
necessarily  causes  an  inward  suction  of  cold  air  which 
is  harmful. 

As  a  rule  with  generators  employing  anthracite  coal, 
it  is  sufficient  to  empty  the  ash-pit  twice  daily;  this 
should  be  preferably  done  during  stoppages.  How- 
ever, the  cleaning  of  the  grate  by  means  of  a  poker 
passed  between  the  grate-bars  or  over  them  in  order 
to  bring  about  the  falling  of  the  ashes,  should  be  at1 
tended  to  every  two  to  four  hours,  according  to  the  type 
of  the  generator  and  the  nature  of  the  fuel.  In  order 
that  this  cleaning  may  be  done  without  opening  the 
doors,  the  latter  should  be  provided  with  apertures  hav- 
ing closing  devices. 

This  cleaning  has  for  its  chief  object  to  allow  the  free 
passage  of  the  air  for  supporting  combustion  and  to 
keep  the  incandescent  zone  in  the  apparatus  at  the 
proper  height.  The  accumulation  of  ashes  and  clinkers 
at  the  bottom  of  the  retort  will  shift  this  zone  upward 
and  impair  the  quality  of  gas. 

Stoppages  and  Cleaning.— After  closing  the  gas- 
'  inlet  to  the  engine,  the  damper  in  the  gas-outlet  flue 
of  the  generator  should  be  opened  and  the  cocks  con- 
trolling the  feed  of  water  to  the  scrubber  and  to  the 
vaporizer  should  be  closed. 


262    GAS-ENGINES    AND    PRODUCERS 

If  it  is  desired  to  keep  up  the  fire  of  the  generator 
during  the  stoppage  so  as  to  be  able  to  start  again 
quickly,  the  ash-pit  door  should  be  opened  so  as  to  pro- 
duce a  natural  draft  which  will  maintain  combus- 
tion. While  the  door  is  open,  the  clinkers  which  have 
accumulated  above  the  grate  may  be  removed,  as  they 
are  much  more  easily  taken  off  the  grate  when  they 
are  hot. 

At  least  once  a  week  the  fire  in  the  generator  should 
be  put  out  and  the  generator  completely  cleaned — that 
is,  when  ordinary  fuel  is  employed.  For  this  purpose, 
as  soon  as  the  apparatus  is  stopped,  a  portion  of  the  in- 
candescent fuel  is  withdrawn  through  the  doors  of  the 
combustion-chamber,  and  the  retort  is  allowed  to  cool 
before  it  is  emptied  entirely.  Too  sudden  a  cooling  of 
the  retort  may  injure  its  refractory  lining.  In  order 
to  prevent  explosions  caused  by  the  entrance  of  air,  the 
feed-hopper  should  remain  hermetically  closed  during 
the  removal  of  the  incandescent  fuel  through  the  doors 
of  the  combustion-chamber. 

If  the  apparatus  is  placed  in  a  room  poorly  venti- 
lated, the  cleaning  should  be  attended  to  by  two  men, 
so  that  one  may  assist  the  other  in  case  he  is  overcome 
by  the  gas.  In  all  cases  there  should  be  a  strict  prohibi- 
tion against  the  use  of  any  light  having  an  exposed 
flame  liable  to  set  on  fire  the  explosive  mixtures  which 
may  be  formed. 

When  the  generator,  after  cooling,  is  completely 
open,  the  charging-box  is  taken  apart,  and,  if  necessary, 
the  feed-hopper  also;  the  grates  are  taken  out,  if  neces- 


STOPPAGES    AND    CLEANING        263 

• 

sary;  and,  by  means  of  a  poker  inserted  from  above,  the 
clinkers  and  slag  adhering  to  the  retort  are  broken 
off. 

In  the  foregoing  paragraphs  the  author  has  indicated 
how  the  several  apparatus,  such  as  the  vaporizer,  the 
washer,  the  conduits,  etc.,  should  be  attended  to  and 
maintained  in  good  working  order. 


CHAPTER    XIV 

OIL  AND  VOLATILE   HYDROCARBON   ENGINES 

ALTHOUGH  this  book  is  devoted  primarily  to  a  dis- 
cussion of  street-gas  and  producer-gas  engines  em- 
ployed in  various  industries,  a  few  words  on  oil  and 
volatile  hydrocarbon  engines  may  not  be  out  of  place. 

Oil-engines  are  those  which  use  ordinary  petroleum 
as  a  fuel  or  illuminating  oil  of  yellowish  color,  having 
a  specific  gravity  varying  from  0.800  to  o.-Sao  at  a  tem- 
perature of  15  degrees  C.  (490  degrees  F.),  and  boiling 
between  140  and  145  degrees  C.  (284  to  297  degrees 
F.).  Volatile  hydrocarbon  engines  are  those  which 
employ  light  oils  obtained  by  distilling  petroleum. 
These  oils  are  colorless,  have  a  specific  gravity  that 
varies  from  0.680  to  0.720,  and  boil  between  80  degrees 
and  115  degrees  C.  (176  to  257  degrees  F.).  Among 
these  "  essences,"  as  they  are  called  in  Europe,  may  be 
mentioned  benzine  and  alcohol. 

In  general  appearance,  and  the  way  in  which  they 
are  controlled,  oil-engines  differ  but  little  from  gas- 
engines.  Their  usual  speed,  however,  is  20  to  30  per 
cent,  greater  than  that  of  gas-engines.  Except  in  some 
engines  of  the  Diesel  and  Banki  types,  the  compression 
does  not  exceed  43  to  71  pounds  per  square  inch.  In 
volatile  hydrocarbon  engines,  on  the  other  hand,  the 

speed  is  very  high,  often  running  from  500  to  2,000 

264 


OIL-ENGINES  265 

0 

revolutions  per  minute,  while  the  speed  of  gas  or  oil 
engines  rarely  exceeds  250  or  300  revolutions  per 
minute. 

Oil  -  Engines. — Oil-engines  are  employed  chiefly  in 
Russia  and  in  America.  Because  of  the  high  price  of 
oil  in  other  countries  they  are  to  be  found  only  in  small 
installations  in  country  regions  and  are  used  mainly 
for  driving  locomobiles  and  launches.  The  improve- 
ments which  have  been  made  of  late  years  in  the  con- 
struction of  gas-engines  supplied  by  suction  gas-pro- 
ducers for  small  as  well  as  for  large  powers,  have  hin- 
dered the  general  introduction  of  oil-engines. 

The  characteristic  feature  in  the  design  of  many  of 
the  oil-engines  of  the  four-cycle  type  now  in  use  (to 
which  type  we  shall  confine  this  discussion)  is  to  be 
found  in  the  controlling  mechanism  employed.  The 
underlying  principle  of  this  mechanism  lies  not  in  acting 
upon  the  admission-valve,  but  in  causing  the  governor 
to  operate  the  exhaust-valve  in  such  a  manner  that  it 
is  held  open  whenever  the  engine  tends  to  exceed  its 
normal  speed.  Some  engines,  however,  are  built  on  the 
principle  of  the  gas-engine,  with  an  admission-valve  so 
controlled  by  the  governor  that  it  is  open  during  nor- 
mal operation  and  closed  whenever  the  speed  becomes 
excessive. 

The  necessity  of  producing  a  mixture  of  air  and  oil 
capable  of  being  ignited  in  the  engine-cylinder  has 
led  to  the  invention  of  various  contrivances,  which 
cannot  be  used  if  illuminating-gas  or  producer-gas  be 
employed.  These  contrivances  are  the  atomizer,  the 


266    GAS-ENGINES    AND    PRODUCERS 

carbureter,  the  oil-pump,  the  air-pump,  the  oil-tank, 
and  the  oil-lamp.  In  some  oil-engines  all  of  the  ele- 
ments may  be  found,  but  for  the  purpose  of  simplifying 
the  construction  and  of  avoiding  unnecessary  complica- 
tions, manufacturers  devised  arrangements  which  ren- 
dered it  possible  to  discard  some  of  them,  particularly 
those  of  delicate  construction  and  operation.  It  is 
not  the  intention  of  the  author  to  enter  into  a  detailed 
description  of  these  various  devices,  since  the  limita- 
tions of  this  book  would  be  considerably  surpassed.  The 
reader  is  referred  to  books  on  the  oil-engine,  published 
in  the  United  States,  England,  and  France.* 

Most  of  the  observations  which  have  been  made  on 
the  construction  and  installation  of  gas-engines,  as  well 
as  the  precautions  which  have  been  advised  in  the  con- 
duct of  an  engine,  apply  with  equal  force  to  oil-engines. 
It  will  therefore  be  unnecessary  to  recur  to  this  phase 
of  the  subject  so  far  as  oil-engines  are  concerned.  One 
point  only  should  be  insisted  upon — the  necessity  of 
very  frequently  cleaning  the  valves  and  moving  parts 
of  the  engine. 

Illuminating-oil  when  burnt  produces  sooty  deposits, 
particularly  if  combustion  be  incomplete,  which  de- 
posits foul  the  various  parts  and  cause  premature  igni- 
tions and  faulty  operation. 

*  Hiscox,  Gas  and  Oil  Engines,  Norman  W.  Henley  Pub.  Co.,  New 
York.  Parsell  and  Weed,  Gas  and  Oil  Engines,  1900,  Norman  W. 
Henley  Pub.  Co.,  New  York.  Goldingham,  1900,  Spon  &  Chamberlain, 
London.  Dugald  Clerk,  1897,  Longmans,  London.  Grover,  1902,  Hey- 
wood,  Manchester.  Aime  Witz,  1904,  Barnard,  Paris.  H.  Giildner,  1903, 
Springer,  Berlin. 


HYDROCARBON    ENGINES  267 

t  . 

The  use  of  oil  in  atomizers,  carbureters,  and  lamps 
is  accompanied  with  the  employment  of  pipes  and  open- 
ings so  small  in  cross-section  that  the  slightest  negligence 
is  attended  with  the  formation  of  partial  obstructions 
that  inevitably  affect  the  operation  of  the  engine. 

Volatile  Hydrocarbon  Engines. — Only  those  en- 
gines will  here  be  treated  which  have  become  of  im- 
portance in  the  development  of  the  automobile. 

Some  designers  have  attempted  to  employ  the  vola- 
tile hydrocarbon  engine  for  industrial  and  agricultural 
purposes,  and  have  devised  electro-generator  groups, 
hydraulic  groups,  and  so-called  "  industrial  combina- 
tions "  in  which  belt  and  pulley  transmission  is  em- 
ployed. These  applications  in  particular  will  here  be 
rapidly  reviewed. 

The  high  speed  at  which  engines  of  this  class  are 
driven  renders  it  possible  to  operate  a  centrifugal  pump 
directly  and  to  mount  both  the  engine  and  machine 
which  it  actuates  on  the  same  base.  The  hydrocarbon 
engine  has  the  merit  of  being  very  light  and  of  taking 
up  but  little  room.  Its  cost  is  considerably  less  than 
that  of  an  oil  or  producer-gas  engine  of  corresponding 
power.  On  the  other  hand,  its  maintenance  is  much 
more  expensive,  and  the  hydrocarbons  upon  which  it 
depends  for  fuel  anything  but  cheap.  Furthermore, 
the  engines  wear  away  rapidly,  on  account  of  their  high 
speed.  For  this  reason  it  is  advisable  to  base  calcula- 
tions on  a  life  of  three  to  four  years,  while  oil  and  gas 
engines  may  generally  be  considered  to  be  still  of  ser- 
vice at  the  end  of  thirteen  years.  On  the  following 


268    GAS-ENGINES    AND    PRODUCERS 

page  a  comparison  of  costs  for  installation  and  main- 
tenance is  drawn  between  the  oil  and  hydrocarbon 
engine  on  the  basis  of  ten  horse-power. 

Comparative  Costs. — A  10  horse-power  oil-engine, 
in  the  matter  of  first  cost  of  installation,  is  about  35 
per  cent,  more  expensive  than  a  volatile  hydrocarbon 
engine  of  equal  power.  On  the  other  hand,  the  operat- 
ing expenses  of  the  oil-engine  are  less  by  25  per  cent, 
than  they  are  for  the  volatile  hydrocarbon  engine. 

The  engines  which  are  here  discussed  usually  have 
their  cylinders  vertically  arranged,  as  in  steam-engines 
of  the  overhead  cylinder  type.  The  crank-shaft  and 
the  connecting-rods  are  enclosed  in  a  hermetically 
sealed  box  filled  with  oil,  so  that  the  movement  of  the 
parts  themselves  ensures  the  liberal  lubrication  of  the 
piston.  The  suction-valve  is  generally  free,  although 
latterly  designers  have  shown  a  tendency  to  connect 
it  with  the  cam-shaft,  with  the  result  that  it  has  become 
possible  to  reduce  the  speed  appreciably  without  stop- 
ping the  engine.  The  carbureter  is  operated  by  the 
suction  of  the  engine.  If  the  fuel  employed  is  alcohol, 
it  must  be  heated. 

Tests  of  High-speed  Engines. — High-speed  engines 
present  various  difficulties  which  must  be  contended 
with  in  controlling  their  operation.  Their  high  speed 
renders  it  impossible  to  take  indicator  records  as  in  the 
case  of  most  industrial  engines.  Indicator  cards,  more- 
over, at  best  give  but  very  crude  data,  which  relate  to 
each  explosion  cycle  only,  and  which  are  therefore  in- 
adequate in  determining  the  exact  conditions  of  an  en- 


EXPLOSION    RECORDS  269 

9 
gine's  operation.    Oil,  benzine,  and  other  so-called  car- 

bureted-air  engines  are  particularly  difficult  to  control 
because  of  many  phenomena  which  cannot  be  recorded. 
In  order  to  test  the  operation  of  high-speed  engines, 
two  different  types  of  instruments  are  at  present  em- 
ployed: the  manograph  and  the  continuous  explosion 
recorder. 

The  Manograph. — The  manograph,  which  is  the 
invention  of  Hospitalier,  is  an  optical  instrument  in 
which  a  series  of  closed  diagrams  are  superimposed 
upon  a  polished  mirror  similar  in  form  to  Watt 
diagrams.  Because  the  images  persist  in  affecting  the 
retina  of  the  eye  an  absolutely  continuous,  but  tem- 
porary, gleam  is  seen.  Still,  it  is  possible  to  obtain  a 
photograph  or  a  tracing  of  these  diagrams. 

The  Continuous  Explosion  Recorder  for  High- 
speed Engines. — The  author  has  devised  an  explo- 
sion and  pressure  recorder,  which  is  mounted  upon  the 
explosion  chamber  to  be  tested  and  which  communi- 
cates with  the  chamber  through  the  medium  of  a 
cock  r  (Fig.  136) .  The  instrument  is  somewhat  similar 
in  form  to  the  ordinary  indicator.  Its  record,  however, 
is  made  on  a  paper  tape  which  is  continuously  un- 
wound. The  cylinder  c  is  provided  with  a  piston  />, 
about  the  stem  of  which  a  spring  s  is  coiled.  A  clock 
train  contained  in  the  chamber  b  unwinds  the  strip  of 
paper  from  the  roll  p'  and  draws  it  over  the  drum  />', 
where  the  pencil  t  leaves  its  mark.  The  tape  is  then 
rewound  on  the  spindle  p'".  A  small  stylus  or  pencil  f 
traces  "  the  atmospheric  line  "  on  the  paper  as  it  passes 


270    GAS-ENGINES    AND    PRODUCERS 

over  the  drum  p".     In  order  to  obviate  the  binding  of 
the  piston  p  when  subjected  to  the  high  temperature  of 


FIG.  136. — R.  Mathot's  continuous  explosion  recorder. 

the  explosions,  the  cylinder  c  is  provided  with  a  casing 
e  in  which  wat^r  is  circulated  by  means  of  a  small  rub- 
ber tube  which  fits  over  the  nipple  e '.  This  recorder 


THE    EXPLOSION    RECORDER       271 

9  • 

analyzes  with  absolute  precision  the  work  of  all  en- 
gines, whatever  may  be  their  speed.  It  gives  a  con- 
tinuous graphic  record  from  which  the  number  of  ex- 
plosions, together  with  the  initial  pressure  of  each,  can 
be  determined,  and  the  order  of  their  succession.  Con- 
sequently the  regularity  or  irregularity  of  the  variations 
can  be  observed  and  traced  to  the  secondary  influences 
producing  them,  such  as  the  section  of  the  inlet  and  out- 
let valves  and  the  sensitiveness  of  the  governor.  It 
renders  it  possible  to  estimate  the  resistance  to  suction 
and  the  back  pressure  due  to  expelling  the  burnt  gases, 
the  chief  causes  of  loss  in  efficiency  in  high-speed  en- 
gines. Furthermore,  the  influence  of  compression  is 
markedly  shown  from  the  diagram  obtained. 

The  recorder  is  mounted  on  the  engine;  its  piston  is 
driven  back  by  each  of  the  explosions  to  a  height  cor- 
responding with  their  force;  and  the  stylus  or  pencil 
controlled  by  the  lever  t  records  them  side  by  side  on 
the  moving  strip  of  paper.  The  speed  with  which  this 
strip  is  unwound  conforms  with  the  number  of  revolu- 
tions of  the  engine  to  be  tested,  so  that  the  records 
of  the  explosions  are  placed  side  by  side  clearly  and 
legibly.  Their  succession  indicates  not  only  the  num- 
ber of  explosions  and  of  revolutions  which  occur  in 
a  given  time,  but  also  their  regularity,  the  number 
of  •misfires.  The  atmospheric  pressure  of  the  explo- 
sions is  measured  by  a  scale  connected  with  the  re- 
corder-spring. By  employing  a  very  weak  spring 
which  flexes  at  the  bottom  simply  by  the  effect  of 
the  compression  in  the  engine-cylinder,  it  is  possible 


272    GAS-ENGINES    AND    PRODUCERS 


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AMOUNT    OF    COMPRESSION 


273 


to  ascertain  the'amount  of  the  resistance  to  suction  and 
to  the  exhaust.  It  is  simply  sufficient  to  compare  the 
explosion  record  with  the  atmospheric  line,  traced  by 
the  stylus  /.  By  means  of  this  apparatus,  and  of  the 
records  which  it  furnishes,  it  is  possible  analytically  to 
regulate  the  work  of  an  engine,  to  ascertain  the  propor- 
tion of  air,  gas,  or  hydrocarbon,  which  produces  the 
most  powerful  explosion,  to  regulate  the  compression, 
the  speed,  the  time  of  ignition,  the  temperature,  and  the 
like  (Figs.  137,  138  and  139). 

In  order  to  explain  the  manner  of  using  this  recorder 
several  specimen  diagrams  are  here  given. 

I.  Determination  of  the  Amount  of  Compression. — 
A  spring  of  average  power  is  employed,  the  total  flexion 
of  which  corresponds  almost  with  the  maximum  com- 
pression so  as  to  obtain  a  curve  of  considerable  ampli- 
tude. The  engine  is  first  revolved  without  producing 
explosions,  driving  it  from  the  dynamo  usually  em- 
ployed in  shops,  at  the  different  speeds  to  be  studied. 
The  compression  of  the  mixture  varies  in  inverse  ratio 
to  the  number  of  revolutions  of  the  shaft,  owing  to  the 
resistances  which  are  set  up  in  the  pipes  and  the  valves 
and  which  increase  with  the  speed.  The  accompany- 
ing cut  (Fig.  140)  shows  two  distinct  records  taken  in 
two  different  cases,  namely: 

A. — Speed  of  engine,  950  revolutions  per  minute; 
amount  of  compression,  68.9  pounds  per  square  inch. 

B. — Speed  of  engine,  1,500  revolutions  per  minute; 
amount  of  compression,  61  pounds  per  square  inch,  or 
1 1.5  per  cent.  less. 


274    GAS-ENGINES    AND    PRODUCERS 


II.  Determination  of  the  Resistance  to  Suction  and 
Exhaust. — Influence  of  the  tension  of  the  spring  of  the 
suction  valve  and  of  the  section  of  the  pipe.  Effect  of 


14  r 

ATMOSPHERIC  L 


LINE     | 


1 


FIG.  140. 


the  section  of  the  exhaust-valve  and  of  the  length  and 
shape  of  the  exhaust-pipe: 

A  very  light  spring  is  utilized,  the  travel  of  which  is 
limited  by  a  stop  so  as  to  obtain  on  a  comparatively 
large  scale  the  depressions  and  resistance  respectively 
represented  by  the  position  of  the  corresponding  curve, 
above  or  below  the  atmospheric  line  (Fig.  141). 

170.6  Ibs.per  sq.in. 

~ 


ATMOSPHERIC  LINE  f- \^ 


o 


FIG.  141. 

C. — Tension  of  the  suction-valve:  2.9  pounds.  Re- 
sistance to  suction:  \  of  an  atmosphere  (2.7  pounds). 

D. — Tension  of  the  suction-valve:  2.17  pounds.  Re- 
sistance to  suction:  -f-  of  an  atmosphere  (5.4  pounds). 

E.--A  chest  is  used  for  the  exhaust.  Resistance  to 
exhaust:  f  of  an  atmosphere  (^.4  pounds). 

F. — The  exhausted  gases  are  discharged  into  the  air, 


EXPLOSION    RECORDS 


275 


the  pipe  and  the  chest  being  discarded.     Resistance  to 
the  exhaust  is  zero  (Fig.  142). 

The  depression  graphically  recorded  is  partly  due 
to  the  inertia  of  the  spring  of  the  explosion-recorder. 


28,44  !bs.per  sq.in. 


14,22  Ibs.per  sq.in. 

ATMOSPHERIC  I 


FIG.  142. 

which  spring  expands  suddenly  when  the  exhaust  is 
opened. 

III.  Comparison  of  the  Average  Force  of  the  Ex- 
plosions by  Means  of  Ordinates. — A  powerful  spring  is 
employed.  The  paper  band  or  tape  of  the  recorder 
is  moved  with  a  small  velocity  of  translation  so  as  to 
approximate  as  closely  as  possible  the  corresponding 
ordinates  representing  the  explosions  (Fig.  143). 


498  Ibs.per  sq,in. 
427  it 


284 «    «• 

142  «    «    «  «-- 
ATMOSPHERIC  CINE 


The  Norman  W.  Senlty  Pub.  Co,\ 


FIG.  143. 

G. — Pure  alcohol.  Explosive  force,  369.72  to  426.6 
pounds  per  square  inch. 

H. — Carbureted  alcohol.  Explosive  force,  397.6  to 
510.8  pounds  per  square  inch. 

I. — Volatile  hydrocarbon.  Explosive  force,  483.48 
to  531.92  pounds  per  square  inch. 


276    GAS-ENGINES    AND    PRODUCERS 

IV.  Analysis  of  a  Cycle  by  Means  of  Open  Diagrams 
Representing  the  Four  Periods. — A  powerful  spring  is 
employed,  and  the  paper  is  moved  with  its  maximum 
speed  of  translation.  The  four  phases  of  the  cycle  are 
easily  distinguished  as  they  succeed  one  another  graph- 
ically from  right  to  left — in  other  words,  in  a  direction 
opposite  to  that  in  which  the  paper  is  unwound.  A 
diagram  is  made  which  reproduces  exactly  the  values 
of  the  corresponding  pressures  at  different  points  in  the 
travel  of  the  piston  (Fig.  144).  The  periods  of  the 


I 
I 

ATMOSPHERIC  LINE  L- 

Th*  Xorman  W.  Henley  Pub.   Co. 

FIG.  144. 

cycle  are  reproduced  as  faithfully  a$  if  the  ordinary  in- 
dicator which  gives  a  closed  curved  diagram  had  been 
employed.  There  is  no  difficulty  in  reading  the  record, 
since  the  paper  is  not  in  any  way  connected  with  the 
engine-piston.  Some  attempts  have  been  made  to  secure 
open  diagrams  in  which  the  motion  of  translation  given 
to  the  paper  is  controlled  by  the  engine  itself;  but  these 
apparatus  as  well  as  the  ordinary  indicators  cannot  be 
used  when  the  speed  of  the  engine  exceeds  400  to  500 
revolutions  per  minute. 

J. — Speed,  1,200  revolutions;  carbureted  alcohol; 
average  force  of  the  explosions,  426.6  pounds  per 
square  inch.  Average  compression,  92.43  pounds  per 
square  inch.  Pressure  at  the  end  of  the  expansion, 
21.33  pounds  per  square  inch. 


ANALYSIS    OF    RECORDS 


277 


V.  Analysis  of  the  Inertia  of  the  Recorder.  Selection 
of  the  Spring  to  be  Employed. — Given  the  rapidity 
with  which  the  explosions  succeed  one  another  in  auto- 
mobile engines,  it  is  readily  understood  that  the  inertia 
of  the  moving  parts  of  the  recorder  will  be  graphically 
reproduced  (Fig.  144).  The  effect  of  this  inertia  is  a 
function  of  the  weight  of  the  moving  parts  and  of  the 
extent  of  their  travel. 

The  moving  masses  are  represented  by  the  piston  and 
its  rod,  the  spring  and  the  levers  of  the  parallelogram 
stylus.  The  effects  due  to  inertia  have  been  consider- 
ably lessened  by  reducing  the  weight  of  the  various 
parts  to  a  minimum.  A  hollowed  piston,  a  hollowed 
rod  and  short  and  light  levers  have  been  adopted.  The 
traditional  pencil  has  been  displaced  by  a  silver  point 
which  traces  its  mark  upon  a  metallically  coated  paper. 
For  the  heavy  springs  with  their  long  travel,  light  but 
powerful  springs  with  small  amplitudes  have  been  sub- 
stituted. Since  the  perfect  lubrication  of  the  recorder- 
cylinder  is  of  great  importance,  a  simple  oiling  device 
certain  in  its  action  has  been  adopted.  The  recess  of  the 
piston  forms  a  cup  that  can  be  filled  with  oil  whenever 
the  spring  is  changed. 

At  each  explosion  the  violent  return  of  the  piston 
splashes  oil  against  the  cylinder  walls  and  thus  insures 
perfect  lubrication.  It  should  be  observed  that  if  the 
directions  given  are  not  followed,  particularly  in  the 
choice  of  a  spring  suitable  for  each  experiment,  inertia 
effects  will  be  produced.  These  can  easily  be  detected 
on  the  record  and  cannot  be  confused  with  the  curves 


278    GAS-ENGINES    AND    PRODUCERS 

which  interpret  the  phenomena  occurring  in  the  cyl- 
inder of  the  engine.  At  a  height  equal  to  the  end 
of  the  piston's  stroke,  the  cylinder  of  the  recorder  is 
provided  with  a  water-jacket  which  keeps  the  tempera- 
ture down  to  a  proper  point  and  prevents  the  binding  of 
the  piston. 

The  explosion-chamber  of  automobile  engines  being 
rather  small  in  volume,  should  not  be  sensibly  increased 
in  order  that  the  record  obtained  may  conform  as  nearly 
as  possible  with  actual  working  conditions  on  the  road. 
In  order  to  attain  this  end  the  cylinder  of  the  recorder 
is  so  disposed  that  the  piston  travels  to  the  height  of  the 
connecting-cock.  As  a  result  of  this  arrangement  the 
field  of  action  of  the  gases  is  reduced  to  a  minimum. 
Since  these  gases  have  no  winding  path  to  follow,  they 
are  subjected  neither  to  loss  of  quantity  nor  to  cold. 


CHAPTER  XV 

THE  SELECTION  OF  AN  ENGINE 

THE  conditions  which  must  be  fulfilled  both  by  en- 
gines and  gas-producers  in  order  that  they  may  in- 
dustrially operate  with  regularity  and  economy  have 
been  dwelt  upon  at  some  length.  Unfortunately  it  often 
happens  that  engines  are  not  installed  as  they  should  be, 
with  the  result  that  they  run  badly  and  that  the  reputa- 
tion of  gas-engines  suffers  unjustly.  The  use  of  suction 
gas-producers  in  particular  caused  considerable  trouble 
at  first  owing  to  inexperience,  so  that  even  now  many 
hesitate  to  adopt  them  despite  their  great  economical 
advantages.  The  reason  assigned  for  this  hesitation  is 
the  supposed  danger  attending  their  operation. 

The  factory  proprietor  who  intends  to  install  a  gas- 
engine  in  his  plant  is  not  usually  able  to  appreciate  the 
intrinsic  value  of  one  engine  when  compared  with  an- 
other, or  to  determine  whether  the  plans -for  an  installa- 
tion conform  with  the  best  practice.  The  innumerable 
types  of  engines  offered  to  him  by  manufacturers  and 
their  agents,  each  of  whom  claims  to  have  a  better  en- 
gine than  his  rivals,  plunges  the  purchaser  into  hesita- 
tion and  doubt.  Not  knowing  which  engine  to  select,  he 
usually  buys  the  cheapest.  Very  often  he  learns,  as  time 

goes  by,  that  his  installation  is  far  from  being  perfect. 

279 


280    GAS-ENGINES    AND    PRODUCERS 

Finally  he  begins  to  believe  that  he  ought  to  consult  an 
expert.  The  author's  personal  experience  has  con- 
vinced him  that  eight  times  out  of  ten  the  factory  owner 
who  has  picked  out  an  engine  for  himself  has  not  ob- 
tained an  installation  which  meets  the  requirements 
which  the  manufacturers  of  gas-engines  should  fulfil. 
Many  of  these  requirements  could  be  complied  with 
were  it  not  for  the  ,fact  that  the  manufacturer  has 
dropped  certain  details  which  appeared  superfluous, 
but  which  were  in  reality  very  important  in  obtaining 
perfect  operation.  The  author  therefore  suggests  that 
the  services  of  a  competent  expert  be  retained  by  those 
who  intend  to  install  a  gas-engine  in  their  plants. 

The  Duty  of  a  Consulting  Engineer. — An  expert 
fills  the  same  office  as  an  architect,  and  impartially 
selects  the  engine  best  suited  to  his  client's  peculiar 
needs.  His  examination  of  the  engines  offered  to  him 
will  proceed  somewhat  according  to  the  following  pro- 
gramme : 

1.  He   will    first   study    the    installation    from    the 
mechanical  point  of  view,  and  also  the  local  conditions 
under  which  that  installation  is  to  operate,  in  order  that 
he  may  not  order  an  engine  too  large  or  too  small,  or 
a  type  incompatible  with  the  foundations  at  his  dis- 
posal, or  unable  to  fulfil  all  the  requirements  of  his 
client. 

2.  He  will  examine  the  precautions  which  have  been 
taken  to  avoid  or  reduce  to  a  minimum  certain  incon- 
veniences  which   attend   the   operation   of   explosion- 
engines. 


SPECIFICATIONS  281 

;-0l' 

3.  He  will  draw  up  specifications,  with  the  terms 
of  which  gas-engine  makers  must  comply,  so  that  he  can 
compare  on  the  basis  of  these  specifications  the  merits 
of  the  engines  submitted  to  him. 

4.  He  will  prepare  an  estimate  of  cost  and  also  a 
contract  which  is  not  couched  in  terms  altogether  in  the 
gas-engine  maker's  favor,   and  which  gives  the  pur- 
chaser important  warranties. 

5.  He  will  supervise  the  technical  installation  of  the 
engine  or  plant. 

6.  He  will  make  tests  after  the  engine  is  installed  and 
see  to  it  that  the  maker  has  fulfilled  his  warranties. 

Specifications. — Since  engines  and  gas-producers  are 
constructed  for  commercial  ends,  it  naturally  follows 
that  their  manufacturers  seek  to  make  the  utmost  possi- 
ble profit  in  selling  their  installations.  Prices  charged 
will  necessarily  vary  with  the  quality  of  material  em- 
ployed, the  care  taken  in  constructing  the  engine  and 
generator,  the  number  of  apparatus  of  the  same  type 
which  are  manufactured,  the  arrangement  of  the  parts 
and  that  of  the  installations.  Since  there  is  considerable 
rivalry  among  gas-engine  builders,  selling  prices  are 
often  cut  down  so  far  that  little  or  no  profit  is  left.  It 
is  very  difficult — indeed  impossible — to  convince  a  pur- 
chaser that  it  is  to  his  interest  to  pay  a  fair  price  in  order 
to  obtain  a  good  installation,  especially  when  other 
manufacturers  are  offering  the  same  installation  at  a  less 
price  with  the  same  warranties.  As  a  result  of  this  state 
of  affairs,  engine  builders,  in  order  that  they  may  not 
lose  an  order,  are  willing  to  reduce  their  prices,  hoping 


282    GAS-ENGINES    AND    PRODUCERS 

to  make  up  in  the  quality  of  the  workmanship  and  the 
material  what  they  would  otherwise  lose.  Often  they 
will  deliver  an  engine  too  small  in  size  but  operating  at 
a  higher  speed  than  that  ordered;  or  they  will  select  an 
old  type,  or  carry  out  certain  details  with  no  great  care. 
,  This,  to  be  sure,  is  not  always  the  case;  for  there  are 
a  few  builders  of  engines  who  place  their  reputation 
above  everything  else  and  who  would  rather  lose  an 
order  than  execute  it  badly.  Others,  unfortunately, 
prefer  to  have  the  order  at  all  costs. 

By  retaining  a  consulting  engineer,  all  these  diffi- 
culties are  overcome.  In  the  first  place,  the  engineer 
draws  up  a  scale  of  prices  and  specifications  which  must 
be  complied  with  in  their  entirety  as  well  as  in  all  de- 
tails. Rival  engine  builders  are  thus  compelled  to 
make  their  estimates  according  to  the  same  standard, 
so  that  one  engine  can  readily  be  compared  with  an- 
other with  the  utmost  fairness.  In  these  specifications, 
penalties  will  be  provided  for  by  the  engineer  which 
will  be  levied  if  the  warranties  of  the  maker  are  not  ful- 
filled. Otherwise  the  warranties  are  worth  nothing. 

The  first  consequence  of  engaging  a  consulting  en- 
gineer is  to  render  the  matter  of  cost  a  secondary  one. 
A  factory  owner  who  employs  a  consulting  engineer 
and  pays  him  for  his  services,  is  impelled  chiefly  by  the 
desire  to  obtain  a  good  installation  which  will  perform 
what  he  expects  of  it.  For  that  reason  necessary  sacri- 
fices will  be  made  to  comply  with  the  client's  wishes. 

If  the  purchaser  considers  the  question  of  cost  most 
important  to  him,  he  need  not  engage  an  expert  to 


NECESSITY    OF    AN    EXPERT        283 

supervise  the  installation  of  his  engines.  He  has  simply 
to  pick  out  the  cheapest  engine.  Unfortunately,  how- 
ever, the  money  which  he  will  save  by  such  a  procedure 
will  be  more  than  compensated  for  by  the  trouble  which 
he  will  later  experience  when  his  motor  stops  or  when 
it  breaks  down,  because  it  has  been  cheaply  built  in  the 
first  place. 

The  advice  of  a  consulting  engineer  is  therefore  of 
importance  to  the  purchaser,  because  an  engine. will  be 
installed  which  will  in  every  way  meet  his  require- 
ments. The  gas-engine  builder  will  also  prefer  to  deal 
with  an  engineer,  because  the  engineer  can  appreciate 
at  their  true  worth  good  material  and  good  workman- 
ship and  place  a  fair  valuation  upon  them.  The  specifi- 
cations of  a  gas-engine  and  gas-producer  expert  are  ac- 
cepted by  most  engine  builders,  because  an  expert  will 
not  introduce  conditions  which  cannot  be  fulfilled. 
Some  manufacturers  refuse  to  consider  the  conditions 
imposed  by  specifications  seriously,  or  else  they  fix  dif- 
ferent prices  and  make  tenders  on  the  basis  of  these 
with  or  without  specifications.  In  either  case  the  pur- 
chaser may  be  sure  that  he  is  not  receiving  what  he  has 
a  right  to  exact. 

Testing  the  Plant. — When  the  engine  has  been 
selected  the  consulting  engineer  supervises  its  installa- 
tion, and,  after  this  is  completed,  carries  out  tests  in 
order  to  determine  whether  or  not  the  guaranteed 
power  and  consumption  are  attained.  The  methods 
employed  in  testing  a  gas-engine  are  both  complex  and 
delicate.  The  quality  of  the  gas,  the  proportions  of  the 


284    GAS-ENGINES    AND    PRODUCERS 

elements  forming  the  mixture,  the  time  and  the  method 
of  ignition,  the  temperature  of  the  cylinder-walls,  the 
temperature  and  the  pressure  of  the  gas  drawn  into  the 
cylinder,  all  these  are  factors  which  have  a  decided 
bearing  upon  the  results  of  a  test.  If  these  factors  be 
not  carefully  considered  the  conclusions  to  be  drawn 
from  the  test  may  be  absolutely  wrong. 

Indicators  of  any  type  should  not  be  indiscriminately 
employed;  only  those  specially  designed  for  gas-engine 
purposes  should  be  used.  Indicator  cards  are  in  them- 
selves inadequate,  and  should  be  supplemented  by  the 
records  of  explosion-recorders. 

The  calorific  value  of  the  gas  should  be  measured 
either  by  the  Witz  apparatus  or  by  means  of  any  other 
calorimeter. 

In  interpreting  the  diagrams  and  records  some  dif- 
ficulty will  be  encountered.  Sometimes  it  happens  that 
a  particular  form  of  curve  is  attributed  to  a  cause  en- 
tirely different  from  the  real  one.  It  happens  not  infre- 
quently that  engineers,  whose  experience  is  confined  to 
engines  of  one  make  and  who  have  not  had  the  oppor- 
tunity to  make  sufficient  comparisons,  draw  such  erro- 
neous conclusions  from  cards. 

To  recapitulate  what  has  already  been  said,  the  test- 
ing of  gas-engines  requires  considerable  experience  and 
cannot  be  lightly  undertaken.  Special  instruments  of 
precision  are  necessary.  The  author  has  very  often  been 
called  upon  to  contradict  the  results  obtained  by  ex- 
perts whose  tests  have  consisted  simply  in  ascertaining 
the  engine  power  either  by  means  of  a  Prony  brake,  or 


TESTING   THE    ENGINE  285 

9   • 

by  means  of  a  brake-strap  on  the  fly-wheel.  The  brake 
gives  but  crude  results  at  best;  it  is  a  means  of  control, 
and  not  an  instrument  of  scientific  investigation. 

Something  more  than  the  mere  power  produced  by 
an  engine  should  be  ascertained.  The  tests  made  should 
throw  some  light  upon  the  reasons  why  that  power  can- 
not be  exceeded,  and  show  that  the  necessary  changes 
can  be  made  to  cause  the  engine  to  operate  more  eco- 
nomically and  to  yield  energy  of  an  amount  which  its 
owner  has  a  right  to  expect.  The  indicator  and  the 
recorder  are  testing  instruments  which  clearly  indicate 
discrepancies  in  operation  and  the  means  by  which  they 
may  be  corrected.  The  tests  made  should  determine 
whether  the  power  developed  is  not  obtained  largely  by 
means  of  controlling  devices  which  cause  premature 
wearing  away  of  the  engine  parts. 

It  is  not  the  intention  of  the  author  to  describe  indica- 
tors of  the  well-known  Watt  type.  It  is  simply  his  pur- 
pose to  call  attention  to  the  explosion-recorder  which 
he  has  devised  to  supplement  the  data  obtained  by 
means  of  the  indicator. 

Explosion-Recorder  for  Industrial  Engines. — The 
explosion-recorder  illustrated  in  Fig.  145  can  be 
adapted  to  any  ordinary  indicator.  It  is  composed  of 
a  supporting  bracket  B  upon  which  a  drum  T  is 
mounted.  This  drum  is  rotated  by  a  clock-train,  the 
speed  of  which  is  controlled  by  means  of  a  special  com- 
pensating governor.  The  entire  system  is  pivotally 
mounted  upon  the  supporting  screw  O,  so  that  the  drum 
Tf  about  which  a  band  of  paper  is  wound,  may  be 


286    GAS-ENGINES   AND    PRODUCERS 


FIG.  145. — Mathot  explosion-recorder. 


THE    EXPLOSION-RECORDER        287 

swung  against  a  stylus  C,  which  records  upon*  the  paper 
the  number  and  power  of  the  explosions.  These  explo- 
sions are  measured  according  to  scale  by  a  spring  con- 
nected with  an  indicator.  The  records  obtained  dis- 
close for  any  given  cycle  the  amount  of  compression  as 
wrell  as  the  force  of  the  explosion,  and  render  it  possible 
to  study  the  phenomena  of  expansion,  exhaust,  and  suc- 
tion. They  are,  however,  inadequate  in  showing  ex- 
actly how  an  engine  runs  in  general.  Indeed,  in  most 
gas-engines,  as  well  as  oil  and  volatile  hydrocarbon  en- 
gines, each  explosion  differs  from  that  which  follows  in 
character  and  in  power;  and  it  is  absolutely  essential  to 
provide  some  means  of  avoiding  these  variations.  The 
explosion-recorder  gives  a  graphic  record  from  which 
the  number  of  explosions  can  be  read,  and  also  the  ini- 
tial pressure  of  each  explosion,  the  number  of  corre- 
sponding revolutions,  the  order  in  which  the  explosions 
succeed  one  another,  and  consequently  the  regularity  of 
certain  phenomena  caused  by  secondary  influences,  such 
as  the  section  of  the  distributing  members,  the  sensitive- 
ness of  the  governor,  and  the  like. 

The  explosion-records  can  be  taken  simultaneously 
with  ordinary  diagrams.  In  order  to  attain  this  end, 
the  recorder  is  allowed  to  swing  around  the  pivot  O,  so 
that  the  drum  carrying  the  paper  band  is  brought  into 
engagement,  or  swung  out  of  engagement  with  the 
stylus,  as  it  is  influenced  by  each  explosion,  thereby 
leaving  its  record  on  the  paper.  The, ordinary  diagram 
may  be  traced  oh  the  drum  of  the  indicator,  as  it  con- 
tinues to  operate  in  its  usual  way.  Thus  the  explosion- 


288    GAS-ENGINES    AND    PRODUCERS 


recorder  renders  it  possible  to  control  the  operation  of 
engines,  to  obtain  some  idea  of  the  cause  of  defects  and 
to  attribute  them  to  the  proper  force.  Improvements 
can  then  be  made  which  will  ensure  a  greater  efficiency. 
A  number  of  records  herewith  reproduced  illustrate  the 
defects  in  the  controlling  apparatus  and  in  the  construc- 
tion of  certain  engines,  and  also  the  result  of  improve- 
ments which  have  been  made  on  the  basis  of  the  records 
obtained.  The  smaller  lines  indicate  the  compression, 
which  is  usually  constant  in  engines  in  which  the  "  hit- 
and-miss  "  system  of  governing  is  employed,  while  the 
larger  lines  indicate  the  explosions.  These  records  are 
only  part  of  the  complete  data  normally  drawn  on  the 


i 


284.4  Ibs. 


EXPLOSIONS 
BY  THE  ENGINE 


ENGIHE  .RUNNING 
WITH  NO  LOAD 


FIG.  146. — Record  with  automatic  starter. 

paper  in  the  period  of  120  seconds  corresponding  with 
an  entire  revolution  of  the  recorder-drum. 

The  first  record  was  taken  while  starting  up  an  en- 
gine provided  with  an  automatic  starting  device  and 
supplied  with  explosive  mixture  without  previous  com- 
pression (Fig.  146).  The  gradual  lessening  of  the  dis- 
tances of  the  ordinates  or  lines  representing  the  explo- 
sions shows  that  the  speed  of  the  motor  was  slowly 
increasing,  and  also  indicates  the  time  which  elapsed 
before  the  engine  was  running  smoothly.  The  records 
that  follow  (Figs.  147,  148  and  149)  show  the  results 


SELECTION    OF    AN    ENGINE        289 

m 

which  can  be  obtained  with  the  recorder  by  correcting 
the  errors  due  to  faults  in  installing  the  engine  and  its 


1 


WITH  TOO  LONG  AN  EXHAUST-PIPE, 
BY  WHICH  THE  PRODUCTS  OF 
COMBUSTION  WERE  RETAINED 


AFTER  CHANGING  THE  EXHAUST 


FIG.  147. — Gas-engine 'running  at  one-half  load.  • 

accessories.    The  fifth  record  is  particularly  interesting 
because  it  shows  the  influence  of  the  ignition-tube  on 


355.5  Ibs. 


21_313 
99.5 


I 


WITH  INADEQUATE  GAS-PIPE  AFTER  INSERTING  A  LARGER  GAS-PIPE 

The  Xorman  W.  Henley  Pub.  Co. 

FIG.  148. — Record  made  after  correcting  faults. 

the  power  of  the  deflagration  of  the  explosive  mixture 
(Fig.  150).    This  record  was  obtained  with  an  engine 


BECAUSE  OF  THE  SMALL  CROSS  SECTION  OF  THE  PIPES 
THE  EXPLOSIONS  ATTAIN  THEIR  MAXIMUM  EE^ECT 


FIG.  149.  —  Record  made  after  correcting  faults. 

provided  with  two  contiguous  tubes.    The  communica- 
tion of  each  of  these  tubes  with  the  explosion-chamber 


290    GAS-ENGINES    AND    PRODUCERS 

could  be  cut  off  at  will  at  any  moment.  The  last  record 
(Fig.  151)  was  obtained  at  a  time  when  the  effective 
load  of  the  engine  was  changed  at  two  different  inter- 
vals. This  record  shows  how  regularly  the  engine  was 
running  and  how  constant  were  the  initial  pressures. 
These  pressures,  however,  which  is  the  case  in  most 
engines,  manifestly  diminish  when  the  explosions  suc- 
ceed one  another  without  idle  strokes  of  the  piston. 
This  shows,  also,  the  influence  of  "  scavenging "  the 
products  of  combustion  and  the  effect  it  has  on  the 
efficiency  of  explosion-engines. 

Analysis  of  the  Gases. — It  has  already  been  stated 
that  one  of  the  tests  which  should  be  made  consists  in 
measuring  the  calorific  value  of  the  gas.  Just  what  the 
calorific  value  of  the  gas  may  be  it  is  necessary  to  know 
in  order  to  obtain  some  idea  of  the  thermal  efficiency  of 
the  installation.  If  a  suction  gas-producer  be  employed 
(an  apparatus  in  which  the  nature  of  the  gas  generated 
changes  at  each  instant),  calorimetrical  analyses  are  in- 
dispensable in  appreciating  the  conditions  under  which 
a  generator  operates. 

These  analyses  are  made  by  means  of  calorimeters 
which  give  the  calorific  value  either  at  a  constant 
pressure  or  at  a  constant  volume. 

Constant-volume  instruments  give  a  somewhat 
wreaker  record  than  constant-pressure  instruments;  but 
according  to  Professor  Aime  Witz,  the  inventor  of  an 
excellent  calorimeter,  the  constant-volume  type  is  al- 
most indispensable  in  gaging  the  efficiency  of  explo- 
sion-engines. 


EXPLOSION-RECORDS 


291 


!  i 

I    £ 


a 


1 


H 
J  I 

K  ^ 

Q  «*' 


1 


292    GAS-ENGINES    AND    PRODUCERS 

The  Witz  Calorimeter. — The  accompanying  dia- 
gram (Fig.  152)  illustrates  Professor  Witz's  instru- 
ment. Its  elements  are  a  steel  cylinder  having  an  inte- 
rior diameter  of  2.36  inches,  about  a  thickness  of  0.078 
inch  and  a  height  of  about  3.54  inches,  so  that  its  capac- 
ity is  about  15.1  cubic  inches,  and  two  covers  screwed 
on  the  cylinder  to  seal  it  hermetically,  oiled  paper  be- 
ing used  as  a  washer.  The  upper  cover  carries  a  spark- 


FIG.  152. — The  Witz  calorimeter. 

exciter;  the  lower  cover  is  provided  with  a  valve  which 
discharges  into  a  cylindrical  member  1.06  inches  in 
diameter.  This  second  cover  is  downwardly  inclined 
at  its  circumference  toward  the  center  to  insure  com- 
plete drainage  of  the  mercury  used  for  charging  the 
calorimeter.  All  surfaces  are  nickel  plated.  The 
proportions  of  nickel  and  of  steel  are  fixed  by  the 
manufacturer  so  as  to  render  it  possible  to  calculate  the 
displacement  of  the  apparatus  in  water.  The  calo- 
rimeter having  been  completely  filled  with  mercury  is 
inverted  in  this  liquid  in  the  manner  of  a  test  tube.  The 


THE   WITZ    CALORIMETER          293 

;   '0 

explosive  mixture  is  then  introduced,  being  fed  from 
a  bell  in  which  it  has  previously  been  prepared.  A 
rubber  tube  connects  the  bell  with  the  instrument. 
The  gas  is  forced  from  the  bell  to  the  calorimeter  by 
the  pressure  in  the  bell.  The  conical  form  of  the  bot- 
tom causes  the  calorimeter  to  be  emptied  rapidly  and 
to  be  refilled  completely  with  explosive  gas  at  a  pres- 
sure slightly  above  that  of  the  atmosphere.  Equi- 
librium is  re-established  by  manipulating  the  valve, 
during  a  very  short  interval,  so  as  to  permit  the  excess 
gas  to  escape.  During  this  operation  the  calorimeter 
must  be  maintained  in  the  vertical  position  shown  in  the 
diagram.  The  atmospheric  pressure  is  read  off  to  one- 
tenth  of  a  millimeter  (0.003936  inches)  on  a  barometer. 
The  temperature  of  the  gas  may  be  taken  to  be  that  of 
the  mercury-vessel. 

The  explosive  mixture  is  prepared  in  the  water  res- 
ervoir, the  glass  bulb  shown  in  the  accompanying  illus- 
tration being  employed.  This  bulb  is  closed  at  its 
upper  end  by  means  of  a  cock  and  is  tapered  at  its  lower 
end.  The  gas  or  air  enters  at  the  top  by  means  of  a 
rubber  tube  and  gradually  displaces  the  water  through 
the  lower  end.  The  bulbs  have  a  volume  varying  from 
200  to  500  cubic  centimeters  (12  to  30  cubic  inches), 
and  the  error  resulting  from  each  filling  of  a  bulb  is 
certainly  less  than  15  cubic  millimeters  (0.0009  cubic 
inches) .  The  contents  are  emptied  into  a  bell  by  lower- 
ing the  bulb  into  the  water  and  opening  the  cock.  If 
seven  bulbfuls  of  air  be  mixed  with  one  bulbful  of  gas, 
an  explosive  mixture  of  i  to  7  is  produced,  this  being 


294    GAS-ENGINES    AND    PRODUCERS 

the  proportion  commonly  employed  for  street-gas.  For 
producer-gases  the  preferred  proportion  is  i  to  i,  oxy- 
gen being  often  added  to  the  air  in  order  to  insure  com- 
plete combustion. 

The  calorimeter,  after  having  been  filled,  is  placed 
in  a  vessel  containing  a  liter  (1.7598  pints)  of  water 
so  that  it  is  completely  immersed.  A  spark  is  then 
allowed  to  pass.  The  explosion  is  not  accompanied  by 
any  noise;  the  temperature  rises  a  fixed-  number  of 
degrees,  so  that  the  quantity  of  heat  liberated  can 
easily  be  computed.  Each  division  of  the  thermometer 
is  equal  to  0.01502  C.  The  scale  reading  is  minute, 
each  interval  being  divided  by  ten,  so  that  readings  to 
the  i, ^ooth  part  of  a  degree  can  be  taken. 

It  should  be  observed  that  the  mixture  generated  in 
the  reservoir  is  saturated  with  water  vapor  at  the  tem- 
perature of  the  reservoir.  Consequently,  the  vapor 
generated  by  the  explosion  must  condense  in  the  calo- 
rimeter if  the  final  temperature  of  the  calorimeter  is  the 
same  as  that  of  the  water  reservoir.  If,  on  the  other 
hand,  the  temperature  be  slightly  different,  a  correction 
must  be  made ;  but  the  error  is  negligible  for  differences 
in  temperature  of  from  2  to  3  degrees  C.  (3.6  to 
5.4  degrees  F.).  This,  however,  is  never  likely  to 
occur  if  the  operation  is  conducted  under  favorable 
conditions. 

This  apparatus  is  exceedingly  simple  and  practical. 
It  does  not  require  the  manipulation  of  a  pump.  The 
pressure  of  the  mixture  is  read  off  on  the  barometer;  the 
calorimeter  is  entirely  immersed  in  the  water  of  the 


or  THE 
UNIVERSITY* 

OF 


MAINTENANCE    OF    PLANTS 

i 

outer  vessel,  so  that  all  corrections  of  doubtful  accuracy 
are  obviated.  The  method  requires  but  a  very  slight 
correction  for  temperature.  Air,  alone  or  mingled  with 
oxygen,  or  a  mixture  of  air  and  oxygen,  can  be  easily 
tested  with. 

Maintenance  of  Plants.  —  If  it  should  be  necessary 
to  retain  a  consulting  engineer  to  install  an  engine 
capable  of  filling  all  requirements,  it  is  also  necessary 
to  select  a  careful  attendant  in  order  that  the  engine 
may  be  kept  in  good  condition.  It  is  a  rather  wide- 
spread belief  that  a  gas-engine  can  be  operated  without 
any  care  or  inspection.  This  belief  is  all  the  more 
prevalent  because  of  the  employment  of  street-gas  en- 
gines, which,  by  reason  of  their  simplicity  of  construc- 
tion and  regularity  of  fuel  supply,  often  run  for  several 
hours,  and  even  for  an  entire  day,  without  any  attention 
whatever.  But  this  negligence,  particularly  in  the  case 
of  engines  driven  from  producers,  is  likely  to  produce 
disastrous  results.  Although  engines  of  this  type  do  not 
require  constant  inspection  during  operation,  still  they 
require  some  attention  in  order  that  the  speed  may  be 
kept  at  a  fixed  number  of  revolutions.  Moreover, 
the  care  of  the  engine,  the  cleaning  of  the  valves  and  of 
the  various  parts  which  are  likely  to  become  dirty,  and 
the  examination  and  cleaning  of  pipes,  should  be  ac- 
complished with  great  care  and  at  regular  intervals. 
This  task  should  be  entrusted  only  to  a  man  of  intelli- 
gence. A  common  workman  who  knows  nothing  of 
the  care  with  which  the  parts  of  an  engine  should  be 
handled  is  likely  to  do  more  harm  than  good. 


296    GAS-ENGINES    AND    PRODUCERS 

The  factory  owner  who  follows  the  instructions 
which  have  been  given  in  this  book  will  avoid  most  of 
the  stoppages  and  the  trouble  incurred  in  engine  and 
generator  installations,  and  may  count  upon  a  steadiness 
of  operation  comparable  with  that  of  a  steam-engine. 

TEST  OF  A  "STOCKPORT"  GAS-ENGINE  WITH 
DOWSON  PRESSURE  GAS  PLANT 

Made   by  R.   Mathot  at  the  Works  of   the  "Union   Electrique* 
Cie,  Brussels,  June  27,   1901 

Piston  Diameter  :    i$%".     Piston  stroke,  22". 
Normal  number  of  revolutions,  210. 

1.  Calorific  value  of  the  coal ^750  B.T.U. 

2.  Nature  and  origin  of  fuel:    Anthracite  coal 

of  Charleroi  (Belgium). 

3.  Cost  of  fuel  per  ton  -at  the  mine  ....  $5.50 

4.  Cost  of  fuel  per  ton  at  the  plant ....  $6.39 

5.  Fuel  consumption  per  hour  in  the  generator  .  46.3  Ibs. 

6.  Fuel  consumpton  per  hour  in  the  boiler          .  7  Ibs. 

7.  Proportion  of  ash  in  the  coal       ....  6  per  cent. 

8.  Weight  of  steam  at  66  Ibs.  generated  per 

hour 42.7  Ibs. 

9.  Average  brake  horse-power 53  B.H.P. 

10.  Fuel  consumption  for  gas  per  B.H.P.  per 

hour "...  0.875  Ibs. 

11.  Fuel  consumption  for  steam  per  B.H.P.  per 

hour °-J33  Ibs. 

12.  Total  fuel  consumption 1.008  Ibs. 

13.  Steam  consumption  at  66  Ibs.  pressure  .  0.8 1    Ibs. 

14.  Gas  pressure  at  the  engine i|4  inches 

15.  Weight  of  water  per  B.H.P.  per  hour  for 

cooling  the  cylinder  entering  at  68°  F. 

and  leaving  at  105°  F 51.5  Ibs. 


TEST   OF  A   STOCKPORT   ENGINE     297 

t 

16.  Corresponding  heat  absorbed  in  cooling     .  T97O  B.T.U. 

17.  Average  initial  explosive  pressure  on  piston  324  Ibs. 

18.  Average  pressure  on  piston  per  square  inch  72  Ibs. 

19.  Average  indicated  horse-power  with  85  per 

cent,  misses        .       . 92.5  I.H.P. 

20.  Corresponding  mechan  cal  efficiency      .      .  84  per  cent. 

21.  Corresponding  electric  load 31.950  K.W. 

22.  Cost  of  B.H.P.  per  hour  in  anthracite    .      .  $0.0029 

23.  Cost  of  kilowatt  per  hour  in  anthracite  .      .  $0.0048 

24.  Electric  power  generated  per  B.H.P.      .      .  602.8  W. 

25.  Thermal  efficiency  at   53    B.H.P.   with  85 

per  cent,  explosions 18.5  per  cent. 

TEST  OF  A  20  H.P.  WINTERTHUR  ENGINE 

With  Winterthur  Suction-Producer  made  by  R.  Mathot  at  Winter- 
thur, June  4  and  5,  1902 

DATA  OF  TESTS  WITH  ILLUMINATING  GAS  AND  WITH  FUEL  GAS 

Dimensions  of  Winterthur  Engine — Piston  diameter:  10^/6".  Stroke: 
i6fa".  Compression:  177  pounds  per  square  inch.  Regulation: 
hit  and  miss.  Ignition:  electro-magnetic.  Fly-wheel:  normal, 
with  external  bearing.  Lubrication  of  piston:  with  oil-pump. 
Of  main  bearings,  with  rings  (as  in  dynamos). 

FULL    LOAD   WITH    STREET-GAS 

1.  Number  of  revolutions  per  minute    .      .      .  200 

2.  Corresponding  number  of  explosions      .      .  96  per  cent. 

3.  Net  load  on  brake 120  Ibs. 

4.  Corresponding  effective  power     ....  22  B.H.P,, 

5.  Mean  initial   explosive   pressure  on  piston 

per  square  inch 455  Ibs. 

6.  Average  pressure  on  piston  per  square  inch         78  Ibs. 

7.  Gas  consumption  per  B.H.P.  at  24°  C.  and 

721  mm.  mean  pressure 15*5  cubic  feet 

8.  Gas   consumption   per   B.H.P.    reduced  to 

o°  C.  and  760  mm.  mean  pressure      .       .          13.5  cubic  feet 


298    GAS-ENGINES    AND    PRODUCERS 

HALF   LOAD  WITH    STREET-GAS 

9.  Number  of  revolutions  per  minute    .      .      .  204 

10.  Corresponding  number  of  explosions      .      .  60  percent. 

11.  Net  load  on  brake 60  Ibs. 

12.  Corresponding  effective  power     ....  n.6    B.H.P. 

13.  Gas  consumption  per  B.H.P.  per  hour  at 

24°  C.  and  721  mm.  mean  pressure   .      .          21  cubic  feet 

14.  Gas  consumption  per  B.H.P.  per  hour  at 

o°  C.  and  760  mm.  mean  pressure  .       .          18.3  cubic  feet 

RUNNING   WITH  NO   LOAD   WITH    STREET-GAS 

15.  Number  of  revolutions  per  minute    .      .      .       206 

16.  Corresponding  number  of  explosions      .      .         22  per  cent. 

17.  Total  gas  consumption  per  hour  at  24°  C. 

and  721  mm.  mean  pressure  ....       106  cubic  feet 

1 8.  Maximum  calorific  power  of  gas  per  cubic 

foot 598  B.T.U. 

19.  Thermal  efficiency  with  96  per  cent,  explo- 

sions          31   percent. 

20.  Mechanical  efficiency  with  96  per  cent,  ex- 

plosions    82  per  cent. 

21.  Temperature  of  water  at  the  jacket-inlet     .  •  75  degs.  F. 

22.  Temperature  of  water  at  the  jacket-outlet  130  degs.  F. 

23.  Compression  per  square  inch  on  piston  sur- 

face     178  Ibs. 

24.  Pressure  after  expansion 37  Ibs. 

TEST  OF  WINTERTHUR  PLANT  WITH  PRODUCER-GAS 

1.  Nature  of  fuel.   Belgian  an- hracite,  "Bonne 

Esperance  et  Batterie";    size,  ^  inch. 

2.  Chemical    composit  on :    Carbon,   86.5   per 

cent.;  hydrogen,  3.5  per  cent.;  oxygen 
and  nitrogen,  4.65  percent.;  ash,  5.35  per 
cent. 

3.  Calorific  value  per  pound  of  coal      .      .      .  14200  B.T.U. 


TEST  OF  A  WINTERTKUR  PLANT     299 

4.  Net  calorific  value  per  pound  of  fuel      .       .  15050  B.T.U. 

5.  Price  of  anthracite  delivered  at  the  plant     .  $3-5O  per  ton 

6.  Number  of  revolutions  of  engine  per  minute  200 

7.  Corresponding  number  of  explosions      .  91   percent. 

8.  Load  on  brake        .      .      .      .    :.;.••     .      .      .  106  Ibs. 

9.  Corresponding  effective  horse-power       .      .  20.2  B.H.P. 

10.  Fuel  consumption  at  the  generator  per  hour  16.4  Ibs. 

11.  Fuel  consumed  per  B.H.P.  per  hour      .      .  0.81  Ibs. 

12.  Proportion  of  ash  resulting  from  the  tests    .  6  per  Cent. 

13.  Mean  initial  explosive  pressure  per  square 

inch   .      .      ,      . 4T9-5  Ibs. 

14.  Average  pressure  on  piston  per  square  inch  72.5  Ibs. 

15.  Indicated  horse-power  with  91  per  cent,  ex- 

plosions .      .      .      . 25.4  I.H.P. 

16.  Mechanical  efficiency  .      .      ...      .      .  79  percent. 

17.  Thermal'efficiency  at  the  producer  ...  22  percent. 

1 8.  Water  consumption  per  hour  in  the  scrubber  66  gals. 

19.  Cost  per  B.H.P.  per  hour  in  anthracite       .  62  gals. 

TEST  OF  A  60  B.H.P.  GAS-ENGINE,  TYPE  G  9,  WITH 
A  SUCTION-GAS  PLANT  OF  THE  GASMOTOREN 
FABRIK  DEUTZ 

(Made  at  Cologne,  March  15,  1904,  by  R.  Mathot.) 

DATA    OF   THE   TESTS 

Diameter  of  Piston  =  16.5".      Piston  Stroke  =  18.9" 

FULL   LOAD 

1.  Average  number  of  revolutions  per  minute     188.66 

2.  Corre  ponding  effective  work       .      .      .      .  65.11   B.H.P. 

3.  Average  compression  per  square  inch           .  176      Ibs. 

4.  Average  ;n  tial  explosive  pressure  per  square 

inch    . 397      Ibs. 

5.  Average  final  expansion  pressure       ...  25      Ibs. 

6.  Vacuum  at  suction       .      .      .      .      .      .      .  4 .4  Ibs. 

7.  Average  pressure  on  piston 81       Ibs. 

^8.  Corresponding  indicated  horse-power     .      .  77       I.H.P. 


300    GAS-ENGINES    AND    PRODUCERS 

FUEL 

9.  Nature  of  fuel  :  Anthracite  coal  0.4"  to  0.8" 

10.  Origin:  Coalpit  of  Ze  he,  Morsbach  at  Aix- 

la-Chape  le. 

11.  Chemical  composition  of  coal  : 

Carbon    .      .      .      .   83  .22  %         Sulphur    .      .      .     o  .44  % 
Hydrogen  .      .     3  .31   %         Ash     ....     7  .33  % 

Nitrogen  and  Oxygen  3  .01   %         Water       ...     2.69  % 

12.  Calorific  value.      .      .      .....      „,    .'".'"     13650  B.T.U. 

GAS 

13.  Chemical  composition  of  gas: 

Carbonic  acid      .     6.60  %           Methane.      .      .  0.57  % 

Oxygen     .      .     \     o  .30  %           Carbon  monoxide  24  .30  % 

Hydrogen        .      .    18  .90  %           Nitrogen  ...  49  .33  % 

14.  Calorific  value  of  gas,  combination  water, 

at    59°    F.  constant    vo  ume    reduced    to 

32°  F.  and  atmospheric  pressure  .    '  .      .     140  B.T.U. 

TEMPERATURES 

Engine 

15.  Cooling  water  at  the  inlet  of  the  cylinder- 

head     .      .    .'.      .      .      .      .      •      •<     •       554  deg.  F. 
Temperature  at  the  outlet        .      .     -.      .     109  .5  deg.  F. 

16.  Temperature  at  outlet  of  cylinder     .      .      .     127.5 


Gas-Generator 

17.  Temperature  of  water  in  the  vaporizer  .      .     158.3  deg.  F» 

EFFICIENCIES    AND    CONSUMPTION 

18.  Mechanical  efficiency        .      .      .      .      .i  <  .       84.6  % 

19.  Gross  consumption  of  coal  per  B.  H.  P.  per 

hour  ......  .  •  „     .,    .      .      .         0.86  Ibs. 

20.  Thermal  efficiency  in  proportion  to  the  ef- 

fective work   and  the   gross  consumption 

of  coal  in  the  gas-generator      .      *      .      .       24  .3  % 


TEST  OF  A  DEUTZ   PLANT          301 

• 

HALF  LOAD 

WORK 

1.  Average  number  of  revolutions  per  minute  195  .5 

2.  Corresponding  effective  work       ....  33  .85  B.H.P. 

3.  Corresponding  average  compression       .      .125       Ibs. 

4.  Average  initial  explosive  pressure      .      .      .  258       Ibs. 

5.  Average  final  expansion    ...      .      .      .  18       Ibs. 

6.  Vacuum  at  suction       .      .      .   !  ..      .      .      .         6.8  Ibs. 

7.  Average  mean  pressur    on  piston      .      .      .  46  .2  Ibs. 

8.  Corresponding  indicated  power  ....  45  .  I.H.P. 

9.  Speed  variation  between  full  and  half  load         3  .5  % 

CONSUMPTION 
jo.  Gross  consumption  of  coal  per  B.H.P.  per 

hour   ..    .      .      .      .      .      .•     .      .      .      .         1-155  Ibs. 

RUNNING  WITH   NO   LOAD 

1.  Average  number  of  revolutions  per  minute  199 

2.  Minimum  corresponding  compression    .      .       95  .55  Ibs. 

3.  Average  initial  explosive  pressure      .      .      .  220  Ibs. 

4.  Average  final  expansion   .      ...      .    ..*.'•      o  Ibs. 

5.  Vacuum  at  auction       .      .      .      .      .      .      .         8.8  Ibs. 

6.  Average  pressure  on  piston    .      .      .      .      .       u  .2  Ibs. 

7.  Corresponding  indicated  horse-power     .  n  I.H.P. 

8.  Speed  variation  between  full  load  and  no 

load    ..    .      .      .      .'      /    .  "   .      .      .    -.         5.2  % 

TEST  OF  A  GAS  PLANT  OF  A  FOUR-CYCLE  DOUBLE- 
ACTING  ENGINE  OF  200  H.P.  AND  A  SUCTION-PRO- 
.    DUCER   IN   THE   WORKS    OF   THE   GASMOTOREN 
FABRIK  DEUTZ,  COLOGNE 

March   14  and   15,   1904,  by  Me    rs.  A.  Witz,  R.  Mathot,  and  de 

Herbais 

DATA    OF   THE    TESTS 

Piston  Diameter:  21  ^".    Stroke:  27^".    Diameter  of  Piston-Rods: 
front,  424";  rear,  4T5/ 


302    GAS-ENGINES    AND    PRODUCERS 

ENGINE 

Full  Load  Tests 

1.  Average  number  of  revolutions  per  minute   151.29  and    150.20 

2.  Corresponding  effective  load  .    214.22  B.H. P.  and  222.83  B.H. P. 

3.  Duration  of  the  tests   .      ....      .      .  3  hours  and  10  hours 

4.  Average  temperature  of  water  after  cooling 

the  piston      ....".      .      .      ...  117.5  deg.  F. 

5.  Average  temperature   of  water  after  cool- 

ing the  cylinder  and  valve-seats    .      .      %    135     deg.  F. 

6.  Water  consumption  per  hour  for  cooling  the 

piston       J      -   v-      •      •     '•  .         •      •      •       39gal- 

PRODUCER 

7.  Nature    and    Origin    of  Fuel:     Anthracite 

coal  "  Bonne-Esperance  et  Batterie" 
Herstal,  Belgium. 

8.  Calorific  value  of  fuel 14650  B.T.U. 

9.  Consumption  of  fuel  per  hour  (plus  53  Ibs. 

on  the  night  of  the  I4th  for  keeping  the 
generator  fired  during  14  hours,  the  en- 
gine being  stopped) 199  Ibs. — 160  Ibs. 

10.  Water  consumption  per  hour  in  the  vapor- 

iser       .  r   .      .      .      .       14.2  gals. 

11.  Water  consumption  per  hour  in  the  scrub- 

bers       .      .     318      gals. 

12.  Average  temperature  of  gas  at  the   outlet 

of  the  generator 55^      ^eg.  F. 

13.  Average  temperature  of  gas  at  the  outlet 

of  the  scrubbers '    .      .       62.5  deg.  F. 

EFFICIENCIES 

14.  Gross  consumption  of  coal  per  B.H. P.  per 

hour 0.927  Ibs. — 0.720  Ibs. 

15.  Consumption  of  coal  per  B.H. P.  after  de- 

duction of  the  water      ...      .      .      .       0.907  Ibs. — 0.705  Ibs. 


TEST  OF  A  200  H.P.   DEUTZ  PLANT    303 


• 


1 6.  Thermal  efficiency  relating  to  the  effective 

H.P.  and   to  the  dry  coal  consumed  in 

the  generator       ........       19  % — 244  % 

17.  Water  consumption  per  B.H.P.  hour: 

For  the  cylinder,  stuffing-boxes  and  valve- 
seat  jackets      ........         4.65      gals. 

For  the  piston  and  piston-rods     .      .  1.75      gals. 

For  the  vaporizer 0.0655  ga^s- 

For  washing  the  gas  in  the  scrubbers      .         1.42      gals. 

1 8.  Water  converted  in  steam  per  Ib.  consumed 

in  the  generator °-l93    ga^s- 


INDEX 


Adjustment  of  gas-engine,  126 

Adjustment  of  moving  parts,  imper- 
fect, 146 

Admission -valve,  binding  of,  152 

Admission,  variable,  55,  56 

Air-blast,  180 

Air-chest,  82 

Air,  displacement  of,  92 

Air,  exclusion  of,  in  producers,  207 

Air,  filtration  of,  82 

Air-heater,  Winterthur,  236 

Air-heaters,  238 

Air-pipe,  82 

Air-pipe,  location  of,  83 

Air-pump,  266 

Air,  regulation  of  supply,  82 

Air  suction,  81 

Air  suction,  resistance  to,  82 

Air  supply  of  producer,  225 

Air-valve,  control  by  engine,  25 

Air  vibration,  92 

Alcohol  as  engine  fuel,  264 

Anthracite,  consumption  of,  in  pro- 
ducers, 200 

Anthracite  in  producers,  190,  201 

Anti-pulsators,  77 

Anti-pulsators,  disconnection  of,  in 
stopping  engine,  132 

Anti-pulsators,  precautions  to  be 
taken  with,  79 

Anti-vibratory  substances,  89 

Ash-pit,  214,  217 

Ash-pit,  Bollinckx,  220 

Ash-pit,  cleaning  of,  261 

Ash-pit,  Deutz,  220 

Ash-pit,  door  of,  220 

Ash-pit,  Wiedenfeld,  220 

Asphyxiation,  169 

Atomizer  of  oil-engines,  265 


B 


Back  firing,  82,  131 

Back  pressure  to  exhaust,  151 


Bags,  arrangement  of,  80 

Bags,  capacity  of,  79 

Bags,  precautions  to  be  taken  with,  79 

Bags,  rubber,  77 

Bark  as  producer  fuel,  193 

Batteries  for  ignition,  31 

Bearings,  adjustability  of,  5 

Bearings,  adjustment  of,  44 

Bearings,  care  of,  123 

Bearings,  lubrication  of,  117 

Bearings,  material  of,  51 

Bearings  of  fly-wheels,  92 

Bearings,  overheated,  146 

Bearings,  over-lubricated,  150 

Bearings,  position  of,  44 

Bell,  gas-holder,  187 

Bell,  Pintsch,  248 

Bell,  volume  of,  187 

Belts,  prevention  of  adhesion  by  oil, 
120 

Benier,  E.,  199 

Benzin  as  engine  fuel,  264 

Binding,  147 

Blast  in  producers,  180,  193,  225 

Blower,  Koerting,  181 

Blower,  Root,  182,  188 

Blowers  for  producers,  181 

Blowing-generators,  169 

Bolts  of  foundation,  91 

Bomb,  Witz,  284,  292 

Boughs  for  coolers,  108 

Box,  charging,  221 

Box,  double  closure  for  charging,  222 

Box,  removable  charging,  225 

Brake  tests,  284 

Branch  pipes,  minimum  diameter  of, 
81 

Bricks  for  foundation,  91 

Brushes,  lifting  of,  when  dynamo- 
engine  is  stopped,  132 

Brush,  purifying,  250 

Burner  of  hot  tube,  how  ignited,  128 

Burner,  regulation  of  fixed,  144 

Bushings,  care  of,  123 

Bushings,  fusion  of,  147 

Bushings  (see  also  Bearings) 

305 


3°6 


INDEX 


Calorimeter,  Witz,  292 

Calorimeters,  284,  290 

Cam,  half-compression,  130,  132 

Cam,  relief,  130 

Cams,  51 

Caps  of  valve-chests,  124 

Carbureter,  266 

Care  during  operation  of  engine,  131 

Casing,  independence  of  frame,  42 

Charging  a  producer,  221 

Charging  the  generator,  259 

Chest  for  exhaust,  83 

Circulation  of  water,  98,  125 

Circulation  of  water,  how  effected, 
102 

Circulation  of  water  in  tanks,  105 

Circulation  of  water,  regulation  of, 
107 

Cleaning  of  producer,  261 

Cleanliness,  necessity  of,  121 

Cleanliness  of  producers,  1 79 

Closures  for  charging-boxes,  223 

Coal  in  producers,  201 

Coal  in  producers,  bituminous,  195 

Coal,  Pennsylvania,  203 

Coal  (see  also  Anthracite) 

Coal,  Welsh,  203 

Cock,  Deutz,  224 

Cock,  Pierson,  224 

Cock  for  charging-box,  223,  224 

Coke  in  producers,  201 

Coke  in  washers,  242 

Combustion -generators,  193 

Combustion,  inverted,  195 

Compression,  determination  of,  273 

Compression,  faulty,  134 

Compression,  high,  154 

Compression  in  Banki  engine,  264 

Compression  in  Diesel  engine,  264 

Compression,  losses  in,  143 

Compression  period,  21 

Compression,  relation  to  power  de- 
veloped, 122 

Compressors  for  producers,  182 

Connecting-rod  bearings,  45 

Connecting-rod  bearings,  rational  de- 
sign of,  45 

Connecting-rod,  lubrication  of,   113, 

TI5 

Consulting  engineer,  advisability  of 
retaining,  282 


Consumption  at  half  load  and  full 
load,  62 

Consumption  at  various  loads,  62 

Consumption  in  double  or  triple  act- 
ing engines,  62 

Consumption  of  gas,  173 

Consumption  of  gas  in  burner,  30 

Consumption    of    suction -producers, 
200 

Consumption     per    effective    horse- 
power, 62 

Cooler  for  gas,  199 

Cooler,  for  producer,  240 

Coolers,  107 

Coolers,  size  of,  109 

Cooling  of  cylinder,  98,  100,  156 

Cooling  of  producer-gas  engines,  203 

Cooling,  thermo-siphon,  100 

Cost  of  oil  and  volatile  hydrocarbon 
engines,  268 

Crank-pin,  tensile  strength  of,  51 

Crank -shaft,  50,  51 

Crank -shaft  bearings,  44 

Crank -shaft  bearings,  design  of,  46 

Crank -shaft,  effect  of  premature  ex- 
plosion on,  30 

Crank-shaft  lubrication,  117 

Crank-shaft,  material  of,  50 

Crosshead,  care  of,  123 

Cycle,  analysis  of,  276 

Cylinder,  arrangement  of,  41 . 

Cylinder,  cleaning  of,  122 

Cylinder,  cooling  of,  156 

Cylinder,  evacuation  of,  83,  131 

Cylinder,  gravel  in,  137 

Cylinder,  grinding  of,  42 

Cylinder,   incandescent   particles  in, 
142 

Cylinder,    independence    of    casing, 
42 

Cylinder-jacket  (see  Water-jacket) 

Cylinder  lubrication,  112 

Cylinder-oil,  112,  149 

Cylinder,  overhang  in  horizontal  en- 
gines, 42 

Cylinder,  overheating  of,  148 

Cylinder,  presence  of  water  in,  136 

Cylinder-sheir,  41 

Cylinder,  smoke  from,  149 

Cylinder,  temperature  during  opera- 
tion of  engine,  132 

Cylinder,  thrust  of,  43 

Cylinder,  tightness -of,  122 


INDEX 


3°7 


Damper,  Pintsch,  224 

Dampers,  223 

Detonations,  untimely,  141 

Distributing  mechanism,  derange- 
ment of,  152 

Drain-cock  in  gas-pipes,  70,  75 

Drain-cocks,  testing  of,  256 

Drier  for  producer-gas,  248 

Dust-collector,  239 

Dust-collector,  Benz,  239 

Dust-collector,  Bollinckx,  239 

Dust-collector,  Pintsch,  239 

Dust-collector,  Wiedenfeld,  239 

Dynamo,  lifting  brushes  from,  in  stop- 
ping engine,  132 


Ebelmen  principle,  195 
Engine,  Banki,  264 
Engine,  Diesel,  264 
Engine,  producer-gas  and  steam,  com- 
pared, 203 

Engine,  selection  of,  279 
Engine,  starting  a  producer-gas,  258 
Engineer,  duty  of  a  consulting,  281 
Engines,  governing  oil,  265 
Engines,  oil,  264,  265 
Engines,  producer-gas,  153 
Engines,    producer-gas,    temperature 

of,  J57 

Engines,  specifications  of,  281 
Engines,  speed  of  oil,  264 
Engines,  tests  of,  268 
Engines,   volatile  hydrocarbon,   264, 

267 

Engines,  writers  on  oil,  266 
Escape-pipes,  228 
Essences,  264 
Exhaust,  83 

Exhaust,  back  pressure  to,  151 
Exhaust,  determination  of  resistance 

to,  274 

Exhaust  into  sewer  or  chimney,  85 
Exhaust,  noises  of,  94,  141 
Exhaust  period,  22 
Exhaust,  water  in,  136 
Exhausters,  183 
Exhaust-chest,  83 
Exhaust-muffler,  86,  94 


Exhaust -pipe,  83,  85 

Exhaust-pipe,  design  of,  96,  97 

Exhaust-pipe,  joints  for,  85 

Exhaust-pipe,  oil  in,  151 

Exhaust -valve,  binding  of,  152 

Exhaust-valve,  cooling  of,  25 

Expansion -boxes,  95 

Expansion  period,  22 

Expert,  necessity  of  an,  282,  283 

Explosion,  spontaneous,  140 

Explosion -engines  (see  Gas-engines) 

Explosion  period,  22 

Explosion -recorder,  analysis  of  inertia 
of,  277 

Explosion -recorder  for  industrial  en- 
gines, 285 

Explosion -recorder,  the  continuous, 
269 

Explosions,  comparison  of  average 
force  of,  275 

Explosion-records,  288 

Explosions,  retarded,  143 


Fans  for  producers,  181 

Feeder,  Winterthur,  236 

Feed-hopper,  224 

Firebox,  door  of,  221 

Flues,  escape,  228 

Fly-wheel,  oil  on,  120 

Fly-wheel,  starting  the,  131 

Fly-wheels,  46 

Fly-wheels  as  pulleys,  46 

Fly-wheels,  balancing  of,  46 

Fly-wheels,  curved  spoke,  how 
mounted,  49 

Fly-wheels,  fastening  of,  46 

Fly-wheels,  proper  mounting  of,  46 

Fly-wheels,  rim  of,  46 

Fly-wheels,  single,  48,  92 

Fly-wheels,  single,  for  dynamo-en- 
gines, 46 

Fly-wheels,  straight  and  curved 
spoke,  49 

Fly-wheels  with  hit-  and-  miss  system, 

5° 

Foundation,  44,  87 
Foundation,  design  of,  88,  89 
Foundation,  excavation  for,  88 
Foundation,  insulation  of,  89,  90 
Foundation  of  dynamo-engine,  91 


3°8 


INDEX 


Frame,  43 

Frame,  method  of  securing,  to  foun- 
dation, 44 

Fuel  of  producers,  178,  187,  254 

Fuel,  qualities  of,  201 

Fuel  (see  also  Lignite,  Peat,  Sawdust, 
Wood,  Coal,  etc.) 

Fuel,  size  of,  201 

Fuel,  smoke-producing,  254 


Gas,  ascertaining  purity  of,  128 

Gas,  blast-furnace,  153 

Gas,  calorific  value  of,  284 

Gas,    calorific    value    of    producer, 

200 

Gas,  coke-oven,  153 
Gas  consumption,  173 
Gas  consumption  of  burner,  30 
Gas,  effect  of  quality,  152 
Gas-engine,  balancing  of,  46 
Gas-engine,    care   during   operation, 

I3I 

Gas-engine,  cost  of  installation,  19 
Gas-engine,  cost  of  operation,  19 
Gas-engine,   difficulties    in    starting, 

i34 

Gas-engine,  how  to  start  a,  128 
Gas-engine,  how  to  stop  a,  132 
Gas-engine,  installation  of  a,  68 
Gas-engine,  location  of  a,  68 
Gas-engine,  selection  of  a,  21 
Gas-engine,  simplicity  of  installation, 

J7 

Gas-engine,  the  four-cycle,  21 
Gas-engines,  adjustment  of,  126 
Gas-engines,  care  of,  121 
Gas-engines,  "  Steam -Hammer,"  57 
Gas-engines,  temperature  of,  158 
Gas-engines,  tests  of,  283 
Gas-engines,  vertical,  56 
Gas-engines,  writers  on,  68 
Gas,  fuel,  153 
Gas-holder,  186,  189 
Gas-holders,  247 
Gas-holder,  combined  with  washer  or 

scrubber,  186 

Gas,  illuminating  (see  Street-gas) 
Gas,  impurities  of,  172 
Gas,  Mond,  153,  167 
Gasometer  (see  Gas-holder) 


Gas,  producer  (see  Producer-gas) 

Gas  production,  1 73 

Gas,  purification  of  wood,  195 

Gas    supply,   necessity  of    coolness, 

69 
Gas-valve,  necessity  of  independent 

operation  of,  27 
Gas,  water,  153,  169 
Gas,  wood,  153,  168 
Gases,  analysis  of,  290 
Generator  (see  also  Producer) 
Generator,  Benz,  207 
Generator,  Bollinckx,  207 
Generator,  care  of,  259 
Generator,  charging  the,  259 
Generator,  construction  of,  177,  207 
Generator,  dimensions  of,  252 
Generator,  Dowson,  177 
Generator,  firing  the,  205,  256 
Generator,  hot  operation  of,  252 
Generator  of  suction  producer,  205 
Generator,  operation  of,  251 
Generator,  Pierson,  215 
Generator,  Pintsch,  207 
Generator,  Taylor,  207 
Generator,  Wiedenfeld,  207 
Generator,  Winterthur,    207 
Generator   with   internal    vaporizer, 

206 

Generators,  blowing,  169 
Generators,  pressure,  169,  177 
Governor,  ball,  52,  53 
Governor,    care    during    operation, 

I3I 

Governor,  hit-and-miss,  52,  54 
Governor,  inertia,  53 
Governor,  sensitiveness  of,  52 
Governors,  53 

Governors,  adjustment  of,  124 
Governors,  care  of,  123 
Governors,  centrifugal,  56 
Governors,  centrifugal,  with  hit-and 

miss  regulation,  55 
Governors  for  oil-engines,  265 
Governors  for  producer-gas  engines, 

161 

Governors,  hit-and-miss,  54 
Governors,  variable  admission,  56 
Grate,  Benier's,  216 
Grate  of  generator-lining,  214 
Grate,  Kiderlen,  216 
Grate,  Pintsch,  216 
Grate,  Wiedenfeld,  216 


INDEX 


3°9 


H 


Heater,  air,  238 

Hit-and-miss  regulation  (see  Gov- 
ernors) 

Holders,  gas,  247 

Hopper,  Bollinckx,  225 

Hopper,  Deutz,  225 

Hopper  for  generator,  224 

Hopper,  removable  feed,  225 

Hopper,  Taylor,  225 

Hopper,  Wiedenfeld,  225 

Hopper,  Winterthur,  225 

Horse-power,  definition  of,  60 

Horse-power,  determination  of,  61 

Horse-power  (see  also  Power) 

Hot  tubes  (see  Tubes) 

Hydrocarbons,  volatile,  for  engine 
fuel,  264 


Ignition,  27,  122 

Ignition,  adjustment  of,  144 

Ignition  by  battery  and  coil,  31 

Ignition  by  magneto,  33 

Ignition,  curing   defects   of   electric, 

J45 
Ignition,  defective,  152 

Ignition,  disadvantages  of  belated, 
28 

Ignition,  disadvantages  of  prema- 
ture, 28 

Ignition,  effect  of  lost  motion,  146 

Ignition,  effect  of  mixture  composi- 
tion on,  28 

Ignition,  effect  of  temperature  of 
flame  on,  28 

Ignition,  effect  of  water  on,  136 

Ignition,  electric,  30,  139 

Ignition,  electric,  regulation  of,  145 

Ignition,  faulty,  143 

Ignition  for  high -pressure  engines,  35 

Ignition,  hot-tube,  159 

Ignition,  imperfect,  137 

Ignition,  objections  to  electric,  31 

Ignition  of  producer-gas,  160 

Ignition,  premature,  139,  142 

Ignition,  premature,  in  high-pressure 
engines,  158 

Ignition,  prevention  of,  by  faulty  com- 
pression, 134 


Ignition,  proper  timing  of,  27 

Ignition,  spontaneous,  140,  159 

Ignition,  tests  prior  to  starting  en- 
gine, 129 

Ignition -tubes  (see  Tubes) 

Incrustation  of  water-jacket,  98,  148 

Incrustation,  prevention  of,  107 

Incrustations,  255 

Indicators,  285 

Indicator-records,  127 

Induction-coil,  32 

Installation,  laws  governing  gas- 
engine,  86 


Joints,  125 
Joints,  care  of,  124 


Laming  mass,  246 

Laws  governing  gas-engines,  86 

Leakage  of  pipes,  69 

Lift -valve  for  charging-box,  223 

Lignite  in  producers,  188 

Lining,  refractory,  211 

Lining,  support  for  generator,  214 

Loads,  consumption  at  half  and  full, 

62 

Location  of  engine,  68 
Lubricate  (see  Oils) 
Lubricating-pumps,  115 
Lubrication,  in,  121 
Lubrication,  difficulties   entailed  by, 

119 

Lubrication,  faulty,  149 
Lubrication  of  crank-shaft,  117 
Lubrication    of    high -power   engine, 

116 

Lubrication  of  valve-stem,  119 
Lubricator,  cotton-waste,  117 
Lubricators,  automatic,  113 
Lubricators,   disconnection  of,  when 

stopping  engine,  132 
Lubricators,   examination  of,   before 

starting,  129 

Lubricators,  feed  of,  121 
Lubricators,  revolving-ring,  118 
Lubricators,  sight-feed,  118 
Lubricators,  types  of,  113 


3-ro 


INDEX 


M 


Magneto,  adaptability  for  producer- 
gas,  35 

Magneto,  control  of,  38 

Magneto,  efficiency  of,  34 

Magneto -igniter,  construction  of,  35 

Magneto  ignition,  33 

Magneto  ignition,  precautions  to  be 
taken,  34 

Magneto,  inspection  of,  before  start- 
ing engine,  129 

Magneto,  mechanical  control  of,  33 

Magneto,  operation  of,  33 

Magneto,  regulation  of,  37 

Maintenance  of  plants,  295 

Manograph,  269 

Mass,  Laming,  246 

Meters,  capacity  of,  70 

Meters,  dry,  72 

Meters,  evaporation  in  wet,  70 

Meters,  falsification  of  records,  70 

Meters,  inclination  of,  71 

Meters,  size  of,  71 

Misfire,  137 

Mixture,  effect  of  high    compression 

in>  155 
Mixture,  effect  of  high  pressure  on, 

156 

Mixture,  governing  by  varying  the, 
161-164 

Mixture,  poorness  of,  143 

Mixture,  pressure  of,  26 

Mixture-valve,  necessity  of  independ- 
ence of  operation  of,  27 

Mortar  for  foundation,  87 

Motion,  lost,  146 

Muffler  for  exhaust,  86,  94 


N 

Naphthalene  in  gas-pipes,  70 
Noises,  cause  of,  92 
Noises  of  exhaust,  94 


Oilers  (see  Lubricators) 
Oiling  (see  Lubrication) 
Oil,  addition  of  sulphur  to,  147 
Oil,  cylinder,  149 
Oil-engines,  264,  265 


Oil-engines,  governing,  265 
Oil-engines,  speed  of,  264 
Oil-engines,  writers  on,  266 
Oil  for  engine  fuel,  264 
Oil,  freezing  of,  150 
Oil-guard  for  fly-wheel,  120 
Oil-lamp,  266 

Oil,  prevention  of  spreading  on  fly- 
wheel, 1 20 
Oil-pumps,  115,  226 
Oil,  quality  of,  150 
Oil,  splashing  of,  119 
Oil-tank,  266 
Oils,  how  tested,  112 
Oils,  mineral  for  lubrication,  112 
Oils,  purification  of,  113 
Oils,  quality  of,  112 
Oils,  requisites  of,  112 
Operation,  steadiness  of,  52 
Otto  cycle,  21 
Overheating,  152 
Overheating,  prevention  of,  147 


Pacini  treatment,  171 

Peat  in  producers,  188 

Perturbations,  134 

Petrol  (see  Oil) 

Pipe-hangers,  86 

Pipes,  69 

Pipes,  cross-section  of,  70 

Pipes,  disposition  of,  77 

Pipes,  escape,  228 

Pipes,  exposure  to  cold,  69 

Pipes  for  exhaust,  83 

Pipes  for  producer-gas,  249 

Pipes  for  water-tanks,  102,  103,  105 

Pipes,  hanging  of,  86 

Pipes,  insulation  from  foundations 
and  walls,  94 

Pipes,  leakage  of,  69 

Pipes,  minimum  diameter  of  branch, 
81 

Pipes,  proper  size  of,  70 

Piston,  39,  122 

Piston,  avoidance  of  insertions  or 
projections,  39 

Piston,  cleaning  of,  141 

Piston,  curved  faces  inadvisable,  39 

Piston,  direct  connection  with  crank- 
shaft, 43 


INDEX 


Piston,  finish  of,  41 

Piston,  importance  of,  in 

Piston,  leakage  of,  136 

Piston,  overheating  of,  148 

Piston,  position  of,  in  starting,  130 

Piston,  rear  face  of,  39 

Piston-pin,  construction  of  bearing 
at,  40 

Piston-pin,  location  of,  41 

Piston-pin,  locking  of,  40 

Piston-pin,  lubrication  of,  113 

Piston-pin,  material  of,  40,  51 

Piston-pin,  strength  of,  40 

Piston-rings,  fouling  of,  149 

Piston-rings,  material  of,  41 

Piston-rings,  number  of,  41 

Piston-rod,  effect  of  premature  ex- 
plosion on,  30 

Piston-wear,  40 

Poisoning,  carbon  monoxide,  170 

Porcelain  of  spark-plug,  32 

Power,  definition  of,  60 

Power,  measuring  engine,  285 

Power,  "  Nominal,"  61 

Precautions  to  be  taken  in  starting, 
128 

Pressure,  back,  to  exhaust,  151 

Pressure-generators,  169,  177 

Pressure  in  producer-gas  engines,  160 

Pressure-lubricators,  114 

Pressure-producers,  1 74 

Pressure-regulator,  bell  as,  187 

Pressure-regulators,  77 

Pressure-regulators,  their  construc- 
tion, 78 

Pressures,  high,  in  producer-gas  en- 
gines, 154 

Preheaters,  229 

Producer,  assembling,  253 

Producer,  Benier,  216 

Producer,  Benz,  228,  239,  240 

Producer,  Bollinckx,  206,  220,  225, 
228,  234,  239 

Producer,  Chavanon,  229 

Producer,  cleaning  of,  261 

Producer,  Dawson,  174 

Producer,  Deschamps,  198 

Producer,  Deutz,  206,  220,  224,  225, 
228,  229,  240 

Producer,  Deutz,  231,  232 

Producer,  Deutz  lignite,  188 

Producer,  Duff,  195 

Producer,  Fange-Chavanon,  198 


Producer,  Fichet-Heurty,  240,  245 
Producer,  Gardie,  183 
Producer-gas,  153 
Producer-gas,  165 
Producer-gas  as  a  furnace  fuel,  177 
Producer-gas,  calorific  value  of,  200 
Producer-gas,  composition  of,  166 
Producer-gas  plants,  tests  of,  297 
Producer-gas,  writers  on,  154 
Producer,    general    arfangement    of 

suction,  204 
Producer,  Goebels,  206 
Producer,  Hille,  206,  239 
Producer,  Kiderlen,  206 
Producer,  Kiderlen,  216 
Producer,  Koerting,  232 
Producer,  Lencauchez,  212,  214 
Producer,  Phoenix,  217 
Producer,  Pierson,  224,  229 
Producer,  Pintsch,  206,  216,  224,  231, 

232,  239,  245,  248 
Producer,  Riche,  168,  190,  193,  195, 

216 

Producer  (see  also  Generator) 
Producer,  stoppage  of,  261 
Producer,  Taylor,  206,  214,  225,  231, 

232 

Producer,  test  by  smoke,  254 
Producer,  test  of  Deutz,  298 
Producer,  test  of  Dowson,  296 
Producer,  tests  of  Winterthur,  297 
Producer,  Thwaite,  195 
Producer,  Wiedenfeld,  206,  216,  220, 

225,  234,  239 

Producer,  Winterthur,  225,  228,  236 
Producers,    advantages    of    suction, 

199 

Producers,  combustion,  193 
Producers,  conditions  of  perfect  oper- 
ation, 251 
Producers,  consumption    of    suction, 

200 

Producers,  distilling,  190 
Producers,  efficiency  of,  201 
Producers,  efficiency  of  lignite,  190 
Producers,  efficiency  of  wood,  194 
Producers,  lignite,  188 
Producers,  maintenaace  of,  254 
Producers,  peat,  i8S 
Producers,  pressure,  174 
Producers,  self-reducing,  193 
Producers,  specifications  of,  281 
Producers,  suction,  199 


312 


INDEX 


Producers,  suction  (see  also  Suction- 
producers) 

Producers,  tests  of,  297 

Producers  with  external  vaporizers, 
206 

Production' of  gas,  173 

Pulley,  disconnection  of,  in  stopping 
engine,  132 

Pump,  circulating  with  by-pass,  106 

Purifier,  fiber,  185 

Purifier,  Fichet-Heurtey,  245 

Purifier,  material  for,  245 

Purifier,  moss,  185 

Purifier,  Pintsch,  245 

Purifier,  sawdust,  185 

Purifiers  for  gas,  184 

Purifiers  for  producer-gas,  244 


Recorder,  analysis  of  inertia  of  ex- 
plosion, 277 

Recorder,  explosion,  for  industrial  en- 
gines, 285 

Recorder,  the  continuous  explosion, 
269 

Records  of  engines,  284 

Records  of  explosions,  288 

Records,  indicator,  127 

Regrinding  of  valves,  122 

Regularity,  cyclic,  48,  53 

Remagnetization  of  magnetos,  33 

Resuscitation  after  asphyxiation,  171 

Retort,  cleaning  of,  225 

Retort  of  producer,  190 

Retort,  support,  214 

Revolutions,  variations  in  number  of, 
52 

Rollers,  51 

Running,  steadiness  of,  52 


Sand  for  foundation,  87 

Sawdust  in  producers,  193 

Scavenging,  142,  155 

Scrubber,  189,  199 

Scrubber,  combined  with  gas-holder, 

186 

Scrubber  for  producer-gas,  240 
Scrubber,  size  of,  253 
Selection  of  gas-engine,  21 


Shavings  in  producers,  193 

Slide-valve  for  charging-box,  223 

Slide-valve,  its  disadvantages,  23 

Sluice-valves,  101 

Smoke  from  cylinder,  149 

Spark-plug,  32 

Specifications  -of  engines,  281 

Specifications  of  producers,  281 

Speed,  how  to  increase,  124 

Speed  of  oil-engines,  264 

Speed  of  volatile  hydrocarbon  en- 
gines, 264 

Speed,  variation  of,  with  load,  52 

Spokes  of  fly-wheels,  49 

Spring  for  valves  (see  Valves) 

Springs,  selection  of,  for  explosion- 
recorder,  277 

Starter,  Tangye,  65 

Starting  an  engine,  128 

Starting,  automatic,  63,  130 

Starting  by  compressed  air,  64 

Starting  by  hand,  63 

Starting  by  hand-pumps,  64 

Starting,  difficulties  in,  134 

Starting,  how  accomplished,  66 

Starting  of  producer-gas  engine,  258 

Steadiness,  52 

Steam-engine,  cost  of  installation,  19 

Steam-engine,  cost  of  operation,  19 

Stoppage  of  producer,  261 

Stopping  the  engine,  132 

Stops,  sudden,  151 

Straw  in  producers,  193,  254 

Street-gas,  165 

Suction,  determination  of  resistance 
to,  274 

Suction,  noises  caused  by,  141 

Suction  of  air,  81 

Suction  period,  21 

Suction-producer,  general  arrange- 
ment of,  204 

Suction-producers,  199 

Suction-producers,  advantages  of,  199 

Suction-producers,  efficiency  of,  201 

Suction-valve,  leakage  of,  142 

Superheater,  Winterthur,  236 

Sylvester  treatment,  171 


Tanks,  connection  of,  105 
Tanks,  design  of,  103 


INDEX 


Tanks,  location  of,  102 

Tanks  for  water-jacket,  how  mounted, 
101 

Tar  in  producer-plants,  200 

Tar,  removal  of,  250 

Tar  (see  also  Scrubber,  Purifier,  etc.) 

Taylor,  A.,  199 

Terminals  of  magneto  apparatus,  34 

Tests  of  gas-engine  plants,  283 

Tests  of  high-speed  engines,  268 

Tests  of  producer-gas  engines,  297 

Thrust-bearings,  51 

Tongue,  traction  of,  in  asphyxiation 
cases,  172 

Tower,  washer,  244 

Town-gas  (see  Street-gas) 

Tree  branches  for  coolers,  107 

Trepidations,  92 

Tube,  gas-supply  pipe  of  incandes- 
cent, 77 

Tube,  incandescent,  27 

Tube,  incandescent,  adjustment  of, 
144 

Tube,  incandescent,  breakage  of,  137 

Tube,  incandescent,  danger  of  break- 
ing, 131 

Tube,  incandescent,  how  started, 
128 

Tube,  incandescent,  leakage  of,  138 

Tubes  as  vaporizers,  231 

Tubes,  incandescent,  28,  159 

Tubes,  incandescent,  valved,  29 

Tubes,  use  of  special  valves  with  in- 
candescent, 29 

Tubes,  valveless  ignition,  28 


Valve-chests,  124 

Valve  mechanism,  slide,  23 

Valve-regrinding,  122,  135 

Valve-stem  lubrication,  119 

Valves,  122 

Valves,  accessibility  of,  25 

Valves,  cooling  of,  25 

Valves,   cooling  of,  in  high-pressure 

engines,  156 

Valves,  defective  operation  of,  135 
Valves,  free,  27 

Valves,  mechanical  control  of,  27 
Valves,  modern,  24 
Valves,  necessity  of  cleanliness,  25 


Valves,  regulation  of,  before  starting, 

129 

Valves,  requisites  of,  25 
Valves,  retardation  in  action  of,  146 
Vaporizer,  Bollinckx,  234 
Vaporizer,  Chavanon,  229,  234 
Vaporizer,  Deutz,  231,  232,  229,  225 
Vaporizer,  Field,  233 
Vaporizer,  internal,  206 
Vaporizer,  Koerting,  232 
Vaporizer,  maintenance  of,  255 
Vaporizer,  operation  of,  234 
Vaporizer,  Pierson,  -229 
Vaporizer,  Pintsch,  231,  232 
Vaporizer-preheaters,  229 
Vaporizer,  size  of,  253 
Vaporizer,  Taylor,  231,  232 
Vaporizer,  Wiedenfeld,  225,  234 
Vaporizers,  external,  206,  230 
Vaporizers,  internal,  229 
Vaporizers,  partition,  234 
Vaporizers,  regulation  of,  236 
Vaporizers,  tubular,  231 
Ventilation  in  engine-room,  69 
Vibration,  89 
Vibration  of  air,  92 
Vibration,  prevention  of,  89,  90 


W 


Water  circulation,  98,  107,  125 

Water  circulation  by  pump,  107 

Water  circulation,  care  during  opera- 
tion, 132 

Water  circulation,  bow  effected,  102 

Water  circulation,  prevention  of 
freezing,  133 

Water-coolers,  106 

Water-coolers,  size  of,  109 

Water  for  circulation,  99 

Water  for  producer-gas  engines,  203 

Water-gas,  153,  167 

Water  in  cylinder,  136 

Water  in  exhaust,  136 

Water-jacket,  41,  98,  125,  157 

Water-jacket,  incrustation  of,  148 

Water-jacket,  outlet  of,  98 

Water-jacket,  prevention  of  incrus- 
tation, 107 

Water-pipe,  102 

Water,  purification  of,  for  circulation^ 
98 


3H 


INDEX 


Water,  running,  for  jacket,  98 

Water-tanks,  101 

Water-tanks,  connection  of,  103,  105 

Water-tanks,  design  of,  103 

Water-tanks,  location  of,  102 

Washer,  Benz,  240 

Washer,   combined  with  gas-holder, 

186 

Washer,  Deutz,  240 
Washer,  Fichet-Heurtey,  240 
Washer  for  gas,  199 
Washer  for  producer-gas,  240 


Washer,  maintenance  of,  256 
Washer,  material  employed  in,  242 
Washer,  Winterthur,  240 
Washers,  184 
Wear,  premature,  146 
Witz  apparatus,  284 
Wood  as  fuel,  254 
Wood,  calorific  value,  194 
Wood-gas,  153,  168 
Wood-gas,  purification  of,  195 
Wood  in  producers,  190,  192,  193 
Work,  definition  of  effective,  60 


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Expert  Opinions  on  Gas  Power  Installations. 

Mechanical  Laboratory  for  Testing  Gas  Engines. 
Chemical  Analyses  of  Fuels. 

Scientific  Investigations. 
Plans  revised  and  corrected  for  mill  and  factory  proprietors. 

Engines  and  power  plants   designed  by  your  own  engineer 
under  my  personal  supervision. 

R.  E.  MATHOT 

BRUSSELS  BELGIUM 


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Appleton's  Cyclopaedia  of  Applied  Mechanics 

This  is  a  dictionary  of  mechanical  engineering  and  the  mechanical  arts,  fully 
describing  and  illustrating  upwards  of  ten  thousand  subjects,  including  agricul- 
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ASKINSON.     Perfumes  and  Their  Preparation.  A  Comprehensive  Treatise 
on  Perfumery 

Containing  complete  directions  for  making  handkerchief  perfumes,  smelling 
salts,  sachets,  fumigating  pastils;  preparations  for  the  care  of  the  skin,  the 
mouth,  the  hair;  cosmetics,  hair  dyes,  and  other  toilet  articles.  300  pages.  32 
illustrations.  8vo.  Cloth,  $3.00. 

BARR.    Catechism  on  the  Combustion  of  Coal  and  the  Prevention  of  Smoke 
A  practical   treatise  for  all   interested   in  fuel   economy   and   rtie   suppression   of 
smoke   from   stationary    steam-boiler   furnaces   and   from   locomotives,     85   illustra- 
tions.    12mo.     349   pages.     Cloth,    $1.50. 

BLACKALL.     Air-Brake  Catechism 

This  book  is  a  complete  study  of  the  air-brake  equipment,  including  the  latest 
devices  and  inventions  used.  All  parts  of  the  air  brake,  their  troubles  and  pecu- 
liarities, and  a  practical  way  to  find  and  remedy  them,  are  explained.  This  book 
contains  over  1,500  questions  with  their  answers,  and  is  completely  illustrated  by 
engravings  and  two  large  Westinghouse  air-brake  educational  charts,  printed  in 
colors.  312  pages.  Handsomely  bound  in  cloth.  18th  edition,  revised  and 
enlarged.  $2.00. 

BLACKALL.     New  York  Air  Brake  Catechism 

This  is  a  complete  treatise  on  the  New  York  Air  Brake  and  Air  Signalling 
Apparatus,  giving  a  detailed  description  of  all  the  parts,  their  operation,  troubles, 
and  the  methods  of  locating  and  remedying  the  same.  It  includes  and  fully 
describes  and  illustrates  the  plain  triple  valve,  quick-action  triple  valve,  duplex 
pumps,  pump  governor,  brake  valves,  retaining  valves,  freight  equipment,  signal 
valve,  signal  reducing  valve,  and  car  discharge  valve.  200  pages,  fully  illus- 
trated. $1.25. 

BUCHETTI.     Engine  Tests  and  Boiler  Efficiencies 

This  work  fully  describes  and  illustrates  the  method  of  testing  the  power  of 
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explained  or  practically  computed.  255  pages;  179  illustrations.  $3.00. 

FOWLER.     Locomotive  Breakdowns  and  Their  Remedies 

This  work  treats  in  full  all  kinds  of  accidents  that  are  likely  to  happen  to 
locomotive  engines  while  on  the  road.  The  various  parts  of  the  locomotives  are 
discussed,  and  every  accident  that  can  possibly  happen,  with  the  remedy  to  be 
applied,  is  given. 

The  various  types  of  compound  locomotives  are  included,  so  that  every  engineer 
may  post  himself  in  regard  to  emergency  work  in  connection  with  this  class  of 
engine. 

For  the  railroad  man  who  is  anxious  to  know  what  to  do  and  how  to  do  it 
under  all  the  various  circumstances  that  may  arise  in  the  performance  of  his 
duties  this  book  will  be  an  invaluable  assistant  and  guide.  250  pages,  fully  illus- 
trated. $1.50. 

FOWLER.     Boiler  Room  Chart 

An  educational  chart  showing  in  isometric  perspective  the  mechanisms  belong- 
ing in  a  modern  boiler  room.  The  equipment  consists  of  water-tube  boilers,. 


Publications   of  The   Norman  W.   Henley   Publishing  Co. 

ordinary  grates  and  mechanical  stokers,  feed-water  heaters  and  pumps.  The 
various  parts  of  the  appliances  are  shown  broken  or  removed,  so  that  the  internal 
construction  is  fully  illustrated.  Each  part  is  given  a  reference  number,  and 
these,  with  the  corresponding  name,  are  given  in  a  glossary  printed  at  the  sides. 
The  chart,  therefore,  serves  as  a  dictionary  of  the  boiler-room,  the  names  of  more 
than  two  hundred  parts  being  given  on  the  list.  25  cents. 

GRIMSHAW.     Saw  Filing  and  Management  of  Saws 

A  practical  handbook  on  filing,  gumming,  swaging,  hammering,  and  the  brazing 
of  band  saws,  the  speed,  work,  and  power  to  run  circular  saws,  etc.,  etc.  Fully 
illustrated.  Cloth,  $1.00. 

GRIMSHAW.     "Shop  Kinks" 

This  book  is  entirely  different  from  any  other  on  machine-shop  practice.  It 
is  not  descriptive  of  universal  or  common  shop  usage,  but  shows  special  ways  of 
doing  work  better,  more  cheaply,  and  more  rapidly  than  usual,  as  done  in  fifty 
or  more  leading  shops  in  Europe  and  America.  Some  of  its  over  .500  items  and 
222  illustrations  are  contributed  directly  for  its  pages  by  eminenl  constructors; 
the  rest  have  been  gathered  by  the  author  in  his  thirty  years'  travel  and  experi- 
ence. Fourth  edition.  Nearly  400  pages.  Cloth,  $2.50. 

<jRIMSHAW.     Engine  Runner's  Catechism 

Tells  how  to  erect,  adjust,  and  run  the  principal  steam  engines  in  the  United 
States.  Describes  the  principal  features  of  various  special  and  well-known  makes 
of  engines.  Sixth  edition.  336  pages.  Fully  illustrated.  Cloth,  $2.00. 

GRIMSHAW.     Steam  Engine  Catechism 

A  series  of  direct  practical  answers  to  direct  practical  questions,  mainly 
intended  for  young  engineers  and  for  examination  questions.  Nearly  1,000  ques- 
tions with  their  answers.  Fourteenth  edition.  413  pages.  Fully  illustrated. 
Cloth,  $2.00. 

GRIMSHAW.     Locomotive  Catechism 

This  is  a  veritable  encyclopaedia  of  the  locomotive,  is  entirely  free  from  mathe- 
matics, and  thoroughly  up  to  date.  It  contains  1,600  questions  with  their  answers. 
Twenty-third  edition,  greatly  enlarged.  Nearly  450  pages,  over  200  illustrations, 
and  12  large  folding  plates.  Bound  in  maroon  cloth,  $2.00. 

HISCOX.     Gas,  Gasoline,  and  Oil  Engines 

Every  user  of  a  gas  engine  needs  this  book.  Simple,  instructive,  and  right 
up  to  date.  The  only  complete  work  on  this  important  subject.  Tells  all  about 
the  running  and  management  of  gas  engines.  Full  of  general  information  about 
the  new  and  popular  motive  power,  its  economy  and  ease  of  management.  Also 
•chapters  on  horseless  vehicles,  electric  lighting,  marine  propulsion,  etc.  412  pages. 
Large  octavo,  illustrated  with  312  handsome  engravings.  Twelfth  edition,  revised 
and  enlarged.  $2.50. 
HISCOX.  Compressed  Air  in  All  Its  Applications 

Gives  the  thermodynamics,  compression,  transmission,  expansion,  and  uses  for 
cower  purposes  in  mining  and  engineering  work;  pneumatic  motors,  shop-tools, 
air-blasts  for  cleaning  and  painting,  air-lifts,  pumping  of  water,  acids,  and  oils; 
aeration  and  purification  of  water-supply,  railway  propulsion,  pneumatic  tube 
transmission,  refrigeration,  and  numerous  appliances  in  which  compressed  air  is 
a  most  convenient  and  economical  vehicle  for  work— with  tables  of  compression, 
expansion,  and  the  physical  properties  of  air.  Large  octavo.  800  pages.  600 
illustrations.  Price,  $5.00. 

HISCOX.     Horseless  Vehicles,  Automobiles  and  Motor  Cycles,  Operated 

by  Steam,  Hydro-Carbon,  Electric,  and  Pneumatic  Motors 

The  make-up  and   management  of  automobile  vehicles  of  all   kinds  are  treated. 

A  complete  list  of  the  automobile  and  motor  manufacturers,  with  their  addresses, 

as    well   as   a    list   of   patents    issued    since   1856    on   the   automobile    industry,    are 

included.     Nineteen  chapters.     Large  8vo.     316  illustrations.    460  pages.    Cloth,  $3.00. 

HISCOX.     Mechanical  Appliances,  Mechanical  Movements  and  Novelties 

of  Construction 

A  complete  and  supplementary  volume  to  the  author's  work,  "Mechanical 
Movements,  Powers,  and  Devices."  Contains  1,000  mechanical  details  and  complex 
combinations  in  mechanical  construction,  which  are  fully  described  and  illustrated, 
including  a  special  and  unique  chapter  explaining  the  leading  conceptions  in  the 
perpetual  motion  idea  existing  during  the  past  three  centuries.  400  pages.  $3.00. 

HISCOX.     Mechanical  Movements,  Powers,  and  Devices 

This  is  a  work  on  illustrated  mechanics,  mechanical  movements,  powers,  and 
devices  covering  nearly  the  whole  range  of  the  practical  and  inventive  field,  for 
the  use  of  mechanics,  inventors,  engineers,  draughtsmen,  and  all  others  inter- 
ested in  any  way  in  mechanics.  Large  8vo.  Over  400  pages.  1,800  specially 
made  illustrations,  with  descriptive  text.  Tenth  edition.  $3.00. 

Inventor's  Manual ;  How  to  Make  a  Patent  Pay 

This  is  a  book  designed  as  a  guide  to  inventors  in  perfecting  their  inventions, 
taking  out  their  patents  and  disposing  of  them.  119  pages.  Cloth.  $1.00. 


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KRAUSS.     Linear  Perspective  Self-Taught 

The  underlying  principle  by  which  objects  may  be  correctly  represented  in 
perspective  is  clearly  set  forth  in  this  book,  everything  relating  to  the  subject 
is  shown  in  suitable  diagrams,  accompanied  by  full  explanations  in  the  text. 
Price,  $2.50. 

LE  VAN.     Safety  Valves  ;  Their  History,  Invention,  and  Calculation 

Illustrated   by   69   engravings.     151   pages.     $1.50. 

M  ATHOT.  Practical  Handbook  on  Gas  Engines  and  Producer  Gas  Plants 
More  than  one  book  on  gas  engines  has  been  written,  but  not  one  has  thus 
far  even  encroached  on  the  field  covered  by  this  handbook.  Above  all,  Mr. 
Mathot's  work  is  a  practical  guide.  Recognizing  the  need  of  a  volume  that  would 
assist  the  gas-engine  user  in  understanding  thoroughly  the  motor  upon  which  he 
depends  for  power,  the  author  has  discussed  his  subject  without  the  help  of  any 
mathematics  and  without  elaborate  theoretical  explanations.  Every  part  of  the 
gas  engine  is4described  in  detail,  tersely,  clearly,  with  a  thorough  understanding 
of  the  requirements  of  the  mechanic.  Helpful  suggestions  as  to  the  purchase 
of  an  engine,  its  installation,  care,  and  operation  form  a  most  valuable  feature 
of  the  work.  Fully  illustrated.  $2.50. 

MONTAGUE.     Mechanical  Drawing  for  Home  Study 

This  is  a  practical  treatise  of  instruction  arranged  for  beginners  and  prepared 
especially  for  home  study. 

Commencing  with  simple  instruction  as  to  the  correct  methods  employed  in 
the  handling  and  care  of  drawing  instruments,  the  author  presents  a  series  of 
problems  in  drafting  construction  that  enables  the  beginner  to  make  substantial 
headway  from  the  very  first. 

Attention  has  been  paid  to  the  matter  of  making  the  text  explicit,  so  that 
there  may  be  no  confusion  arising  from  the  improper  understanding  of  the  sub- 
ject on  the  part  of  the  learner. 

Each  chapter  of  instruction  in  the  principles  of  drawing  is  followed  by  care- 
fully arranged  lessons  to  be  worked  out  by  the  student  in  the  form  of  drawing 
plates,  reduced  copies  of  which  are  shown  in  full-page  illustrations  in  the  text. 
500  pages.  Fully  illustrated. 

PARSELL  &  WEED.     Gas  Engine  Construction 

A  practical  treatise  describing  the  theory  and  principles  of  the  action  of  gas 
engines  of  various  types,  and  the  design  and  construction  of  a  half-horse  power 
gas  engine,  with  illustrations  of  the  work  in  actual  progress,  together  with  dimen- 
sioned working  drawings,  giving  clearly  the  sizes  of  the  various  details.  Second 
edition,  revised  and  enlarged.  Twenty-five  chapters.  Large  8vo.  Handsomely 
illustrated  and  bound.  300  pages.  $2.50. 

REAGAN,  JR.     Electrical  Engineers'  and  Students'  Chart  and  Hand  Book 

of  the  Brush  Arc  Light  System 
Illustrated.     Bound  in   cloth,   with   celluloid   chart  in   pocket.     $1.00. 

SLOANE.     Electricity  Simplified 

The  object  of  "Electricity  Simplified"  is  to  make  the  subject  as  plain  as  pos- 
sible and  to  show  what  the  modern  conception  of  electricity  is.  158  pages.  Illus- 
trated. Tenth  edition.  $1.00. 

SLOANE.     How  to  Become  a  Successful  Electrician 

It  is  the  ambition  of  thousands  of  young  and  old  to  become  electrical  engineers. 
Not  everyone  is  prepared  to  spend  several  thousand  dollars  upon  a  college  course, 
even  if  the  three  or  four  years  requisite  are  at  their  disposal.  It  is  possible  to 
become  an  electrical  engineer  without  this  sacrifice,  and  this  work  is  designed  to 
tell  "How  to  Become  a  Successful  Electrician"  without  the  outlay  usually  spent 
in  acquiring  the  profession.  Twelfth  edition.  189  pages.  Illustrated.  Cloth.  $1.00. 

SLOANE.     Arithmetic  of  Electricity 

A  practical  treatise  on  electrical  calculations  of  all  kinds,  reduced  to  a  series 
of  rules,  all  of  the  simplest  forms,  and  involving  only  ordinary  arithmetic;  each 
rule  illustrated  by  one  or  more  practical  problems,  with  detailed  solution  of  each 
one.  Sixteenth  edition.  Illustrated.  138  pages.  Cloth.  $1.00. 

SLOANE.     Electrician's  Handy  Book 

An  up-to-date  work  covering  the  subject  of  practical  electricity  in  all  its 
branches,  being  intended  for  the  everyday  working  electrician.  The  latest  and 
best  authority  on  all  branches  of  applied  electricity.  Pocket-book  size.  Hand- 
somely bound  in  leather,  with  title  and  edges  in  gold.  800  pages.  500  illustra- 
tions. Price,  $3.50. 

SLOANE.     Electric  Toy  Making,  Dynamo  Building,  and  Electric  Motor 
Construction 

This  work  treats  of  the  making  at  home  of  electrical  toys,  electrical  apparatus, 
motors,  dynamos,  and  instruments  in  general,  and  is  designed  to  bring  within 
the  reach  of  young  and  old  the  manufacture  of  genuine  and  useful  electrical 
appliances.  Fifteenth  edition.  Fully  illustrated.  140  pages.  Cloth.  $1.00. 


Publications   of  The   Norman  W.   Henley   Publishing  Co. 

SLOANE.     Rubber  Hand  Starrips  and  the  Manipulation  tof  India  Rubber 

A  practical  treatise  on  the  manufacture  of  all  kinds  of  rubber  articles.  146 
pages.  Second  edition.  Cloth.  $1.00. 

SLOANE.     Liquid  Air  and  the  Liquefaction  of  Gases 

Containing  the  full  theory  of  the  subject  and  giving  the  entire  history  of 
liquefaction  of  gases  from  the  earliest  times  to  the  present.  It  shows  how  liquid 
air,  like  water,  is  carried  hundreds  of  miles  and  is  handled  i»  open  buckets.  It 
tells  what  may  be  expected  from  it  in  the  near  future.  365  pages,  with  many 
illustrations.  Handsomely  bound  in  buckram.  Second  edition.  $2.50. 

SLOANE.     Standard  Electrical  Dictionary 

A  practical  handbook  of  reference,  containing  definitions  of  about  5,000  distinct 
words,  terms,  and  phrases.  An  entirely  new  edition,  brought  up  to  date  and 
greatly  enlarged.  Complete,  concise,  convenient.  682  pages.  393  illustrations. 
Handsomely  bound  in  cloth.  8vo.  $3.00. 

USHER.     The  Modern  Machinist 

A  practical  treatise  embracing  the  most  approved  methods  of  modern  machine- 
shop  practice,  and  the  applications  of  recent  improved  appliances,  tools,  and 
devices  for  facilitating,  duplicating,  and  expediting  the  construction  of  machines 
and  their  parts.  A  new  book  from  cover  to  cover.  Fifth  edition.  257  engravings. 
322  pages.  Cloth.  $2.50. 

VAN  DERVOORT.     American  Lathe  Practice 

This  is  a  new  book  from  cover  to  cover,  and  the  only  complete  American  work 
on  the  subject,  written  by  a  man  who  knows  not  only  how  work  ought  to  be 
done,  but  who  also  knows  how  to  do  it  and  how  to  convey  this  knowledge  to 
others.  It  is  strictly  up  to  date  in  its  descriptions  and  illustrations,  which  repre- 
sent the  very  latest  practice  in  lathe  and  boring-mill  operations  as  well  as  the 
construction  of  and  latest  developments  in  the  manufacture  of  these  important 
classes  of  machine  tools.  A  large  amount  of  space  is  devoted  to  the  turret  lathe, 
its  modifications  and  importance  as  a  manufacturing  tool.  320  pages.  200  illus- 
trations. $2.00. 

VAN  DERVOORT.     Modern  Machine  Shop  Tools;  Their  Construction, 
Operation,  and  Manipulation,  Including  Both  Hand  and  Machine  Tools 

A  new  work,  treating  the  subject  in  a  concise  and  comprehensive  manner.  A 
chapter  on  gearing  and  belting,  covering  the  more  important  cases,  also  the 
transmission  of  power  by  shafting,  with  formulas  and  examples,  is  included.  This 
book  is  strictly  up-to-date  and  is  the  most  complete,  concise,  and  useful  work 
ever  published  on  this  subject.  Containing  552  pages  and  673  illustrations.  $4.00. 

WOODWORTH.    Dies,  Their  Construction  and  Use  for  the  Modern  Work- 
ing of  Sheet  Metals 

A  practical  work  on.  the  designing,  constructing,  and  use  of  tools,  fixtures,  and 
devices,  together  with  the  manner  in  which  they  should  be  used  in  the  power 
press  for  the  cheap  and  rapid  production  of  sheet  metal  parts  and  articles.  Com- 
prising fundamental  designs  and  practical  points  by  which  sheet  metal  parts  may 
be  produced  at  the  minimum  of  cost  to  the  maximum  of  output,  together  with 
special  reference  to  the  hardening  and  tempering  of  press  tools  and  to  the  classes 
of  work  which  may  be  produced  to  the  best  advantage  by  the  use  of  dies  in  the 
power  press.  Fourth  edition.  400  pages.  500  illustrations.  $3.00. 

WOODWORTH.    Hardening,  Tempering,  Annealing,  and  Forging  of  Steel 

A  new  book  containing  special  directions  for  the  successful  hardening,  and 
tempering  of  all  steel  tools.  Milling  cutters,  taps,  thread  dies,  reamers,  both 
solid  and  shell,  hollow  mills,  punches  and  dies,  and  all  kinds  of  sheet-metal 
working  tools,  shear  blades,  saws,  fine  cutlery,  and  metal-cutting  tools  of  all 
descriptions,  as  well  as  for  all  implements  of  steel,  both  large  and  small,  the  sim- 
plest and  most  satisfactory  hardening  and  tempering  processes  are  presented.  The 
uses  to  which  the  leading  brands  of  steel  may  be  adapted  are  concisely  presented, 
and  their  treatment  for  working  under  different  conditions  explained,  as  are  also 
the  special  methods  for  the  hardening  and  tempering  of  special  brands.  320  pages. 
250  illustrations.  $2.50. 

WOODWORTH.  Modern  Tool  Making  and  Interchangeable  Manufacturing 

This  book  is  a  complete  practical  treatise  on  the  art  of  American  tool  making 
and  system  of  interchangeable  manufacturing  as  carried  on  to-day  in  the  United 
States.  In  it  are  described  and  illustrated  all  of  the  different  types  and  classes 
of  small  tools  fixtures,  devices,  and  special  appliances  which  are  or  should  be  in 
general  use  in  all  machine-manufacturing  and  metal-working  establishments 
where  economy,  capacity,  and  interchangeability  in  the  production  of  machined 

meit1  is  arSoracticalPebookVeDy  an  American  toolmaker  for  practical  men  written 
and  illustrated  in  a  manner  never  before  attempted,  giving  the  twentieth  century 
manufacturing  methods  and  assisting  in  reducing  the  expense  and  increasing  the 
output  and  the  income.  400  pages.  600  illustrations.  $4.00. 


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1-year  loans  may  be  recharged  by  bringing  books 

to  NRLF 
Renewals  and  recharges  may  be  made  4  days 

prior  to  due  date 

DUE  AS  STAMPED  BELOW 


NOV151987 


12690 


U.C. 


BERKELEY  L/BRABIES 


Alrt 


